Merola discovered real tennis while working at Radley College. He worked spells at the International Tennis Club of Washington and the Seacourt Tennis Club before returning to Radley as the senior professional under Chris Ronaldson.[2] Although he entered several major tournaments including the British Open and the US Open, he didn't proceed past the first round between 2016 and 2022.
Merola's breakout came at the 2023 British Open. Winning through qualifying, he beat Louis Gordon in the first round in five sets before taking a set off incumbent World Champion Camden Riviere, the lowest ranked player to do so in over 16 years.[3] In the doubles draw of the same tournament, he and Henry Henman also took a set from Riviere and Tim Chisholm, the incumbent World Doubles Champions.
In 2024, he won the Category A Open in Manchester and was awarded the Most Valuable Player at the IRTPA Super League.[4] He progressed through qualifying at the Champions Trophy and reached the second quarter finals, defeating Bryn Sayers in the first quarter final.[5] At that year's British Open, he reached his first Open singles quarter final, defeating French amateur champion Matthieu Sarlangue in the round of 16. In the doubles, he partnered with Ben Taylor-Matthews and reached the semi final stage, taking another set off of Riviere and Chisholm in the process.[6]
In 2025, Merola reached his first doubles semi final at the US Open, again partnered with Taylor-Matthews. They defeated Lewis Williams and Darren Long in the quarter final. Although he had a disappointing British Open, losing in the first round of both the singles and doubles, followed up at the 2026 Australian Open with the best result of his career, defeating third seed Nick Howell in the quarter-finals to reach his first career singles semi-final.[7] He reached the doubles semi-finals of the same tournament, losing to eventual winners Howell and Steve Virgona.