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Coaching Team

Alexander MacKellar and Keeley Phillips (both former collegiate players with over 17 years of combined coaching) founded the Mack Phillips Tennis Academy in 2019. We offer a tennis experience catering to all age and skill levels. We look forward to sharing our passion and knowledge of the sport with you!

Keeley Phillips
Head Coach

Coach Keeley has been playing tennis seriously for over 8 years and coaching for over 7 years. She attended Cedar Ridge High School where she was awarded team MVP and played #1 mixed doubles. After High School she continued her playing career as a member of the women’s tennis team at Concordia University Texas. She graduated in 2020 with a major in Business Administration and a minor in Kinesiology. Coach Keeley’s favorite things about tennis are its ability to bring communities and families together, and the fact that it is a lifelong sport! Her coaching approach is very tailored to the player and their goals; however, she is a firm believer in creating strong fundamentals to prevent injury and allow players to reach their full potential. She has experience working with kids ages 2 all the way to seniors and all skill levels. When she is not on the court, she enjoys running, baking, DIY projects and spending time with her family.

Alexander Mackellar
Head Coach

Coach Alex began playing tennis at age 11 and has been coaching tennis for over 10 years. He attended Belton High School and was a member of their varsity tennis team. After High School, he joined the United States Navy. He spent 2 years in Washington D.C. at the Nation’s capital as a Ceremonial Guardsman. Then, he spent his last 2 years stationed in Bahrain. After the service, he attended the University of Mary Hardin-Baylor where he was a member of the tennis team and graduated in 2019. After graduating, he knew he wanted to follow his passion, tennis, and has been coaching full time ever since. Coach Alex’s coaching style is always adapted to the individual to best suit their needs and goals.

Stephanie Rodriguez

After taking time to raise a family after playing college tennis, Coach Stephanie was eager to pick up a racquet again to play the game she loves, and she hasn’t looked back! In just a few short years she has become a fixture in the Central Texas tennis scene as a 4.5 league and tournament player competing at the Sectional and National levels. She is also a Round Rock Tennis Association board member and a USTA Tournament and League Committee member. She has leveraged her tennis skills and knowledge to teach an after-school tennis program through Round Rock ISD for elementary age students, and loves conducting private lessons to teach the next generation of tennis players to know and love the game. Coach Stephanie has taught elementary school for 33 years, has been married to her husband for 30 years, and has three grown boys.

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Lisa Robertson

Lisa was introduced to tennis at the age of 6 by her father. She competed all across the great state of Texas to achieve the USTA level of Super Champ at age 14. She also attended Aledo High School where she claimed regional titles in doubles and singles all four years before going on to play at University of North Texas.
Through competing and coaching, her philosophy has always been “The winner is the player who has the most fun”. Tennis is a lifetime sport. Lisa believes having fun is the key ingredient for fostering a lifelong love of the game while developing skills, strength and growth both on and off the court.

Coach Sarah

Coach Sarah Sedory (likes to be called Sedory)  has been playing tennis since she was 8 years old and has been coaching tennis for the past ten years. She graduated from H.M. King HS in Kingsville TX, where she played varsity tennis all four years. Afterwards, she played competitively in college for all four years at the University of Mary Hardin- Baylor and became a graduate assistant coach for one year during her masters program. During her time in Belton, Sedory coached at the University of Texas Longhorn Tennis Camp for 5 years. After graduating from graduate school, Sedory worked at South Belton M.S for one year and then transferred to Kaufman to work at the middle school as a communications teacher and tennis coach. There she coached not only middle school but also high school tennis. The past year she helped coach the varsity team to state for 4A Team Tennis and spring individual. Currently, she works at Active Sports Therapy in Round Rock as the office manager, but still wants to spread her passion of tennis through coaching. Sedory’s coaching goal is to inspire players to love the sport first and then do what it takes to help each player succeed. She enjoys, and is qualified to work with players of all ages and skill levels. She can’t wait to meet you on the court!

Nick Guitron

Hello my name is Nick Guitron and I absolutely love tennis.  I have been playing tennis for 22 years and have made it into a big part of my life.  I played varsity freshman year of highschool, making my way to #1 singles my sophomore year.  Roger Federer is one of my biggest idols and seeing his game convinced me to switch to a one handed backhand senior year. I went on to play tennis for 3 years at Texas Lutheran University, transferring to Texas State to finish my degree in Advertising and graphic design.  After graduating I became a full-time teaching pro at the John Newcombe Tennis Ranch, teaching juniors and adults of all skill levels.  Over the 5 years working there I made my way to adult tennis director.  On the weekends I travel with the Josh Abbott Band managing their merch during their shows, but when I'm not with them I am on court loving the game.  I look forward to working with everyone and will do my best to get you to the level that you want to be at.  See you out there!

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Austin Chumley

Coach Austin (or Coach Chum) started playing tennis at age 5, became the top ranked 10 and 12 year old junior player in Arkansas, and traveled across the South competing in tournaments until age 13. He rekindled his love for tennis in 2020 and has been playing and coaching ever since. Coach Austin graduated from the University of Arkansas in 2019 (Go Hogs) with a Biochemistry Degree. He has a black lab named Bug who is a ball of energy and loves to help pick up tennis balls. Coach Austin played all sports growing up and fully believes that tennis is a lifetime sport; once you develop the skills, they stay with you for life! Coach Austin adapts his coaching strategy to each student individually, helping them achieve their tennis goals. Austin is a sports fanatic, loves skiing and making espresso at home, and competes in triathlons when he is not coaching.

George Hallon

Coach George’s passion for the sport of tennis started as a teenager after hearing about the success his half-brother had as a player including Division 1 as well as ATP tour level. Coach George played the #1 position throughout high school and earned a scholarship to play at St Thomas University (NAIA) as the
#3 position in their tennis team. His tennis coaching experience started at a local summer camp in South Florida. His past experiences in tennis include working at the USTA Florida Section, Grand Slam Sports, Turnberry Isles Resort, and the former Lipton/Sony Erickson open now called Miami Open. George
complements his coaching with customized stringing services at all levels from beginners to ATP tour players. Coach George’s favorite part of tennis is that is a lifelong sport, and his favorite shot is a two-
handed backband.

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Jonathan Darnell

Jonathan Darnell started playing competitive tennis in the 7th grade but has been playing for over 30 years.  He was introduced to the sport at a very young age since his mother was a tennis coach.  He played doubles throughout High School and was a 4-year MVP for the varsity team. He has multiple years of coaching experience with middle school- high school players for multiple different school districts. He has also hosted and led yearly summer camps for players ranging from 1st grade through high schoolers. He has been coaching tennis in some capacity for over 18 years.

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Colette Bellville

Coach Colette has been playing tennis for over 40 years. Growing up her and her brother used to play often. She would play against the high school boys while she chose to do softball and drill team in her high school days. She then started playing USTA competitive leagues in the early 1990s and has never looked back and has now been playing competitive tennis for over 29 years. Since moving to the Round Rock area 16 years ago, she has made the “Top 8 in the State” numerous times and has enjoyed playing the Texas tournament scene. Colette’s day job is a Senior Executive Assistant supporting several top executives. She has always been an avid volunteer when her kids were in school and still volunteers today as President of the Round Rock Tennis Association and has been on that board for five years. In her spare time, she enjoys playing tennis, of course, and spending time with her husband of 33 years and her family, especially her 4 and 6 year old grandchildren.​

Josh Roselius

Hello my name is Joshua Roselius and I have coached tennis for the past four years. I am 22 years old and grew up in College Station, Texas. I started playing tennis at the age of 12 and have been playing/coaching ever since. I was trained by multiple coaches including my father, high school tennis coach, and several college coaches. After I finished up my college tennis journey at the University of Mary Hardin-Baylor, I continued my tennis journey as a coach at The John Newcombe Tennis Ranch (for the past 3-4 years). I have taught adult programs, experienced juniors, and first time juniors. Since January 2021 I have been a full time tennis pro/director on the ranch primarily with the summer/winter junior camps and the year round adult programs.

I am excited to continue my tennis journey and interested in the opportunity to meet people with the same love for the sport

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