The USA's Jack Sock sent down 25 aces in beating Jiri Vesely from the Czech Republic in three sets at the Hopman Cup.
Usually confident with his serve, the American world No.26 said that it had been a weakness in a disappointing 2015.
So it became a focus of his off-season and he even sent down a few extra balls in short training with good friend and Australia's world No.30 Nick Kyrgios, in 42 degree Perth heat on Thursday, before his match.
The hard work is paying off, with Sock's booming serve giving him an edge on Thursday.
After trailing 0-3 to Vesely and then losing the first set, he found some rhythm on his serve to claim the match in three, 4-6 6-2 7-6 (7-3).
His serve gained momentum and the rest of his game followed suit.
"I worked on it a lot in the off season and it feels good right now, so hopefully I can keep it going," Sock said.
"It's the only thing that has really felt good all week.
"From the ground today I felt a lot better, so that is a nice confidence booster going into Auckland next week."
The win was Sock's first of the round robin tournament, having lost to Australia Gold's Lleyton Hewitt and Alex Dolgopolov, of the Ukraine, earlier in the week, both in straight sets.
Vesely, ranked 41, served 19 aces of his own. He claimed the first set with a second break of the Sock serve.
And he was in the match right to the end, losing the third set in a tie-breaker.
The win gave the USA a 1-0 lead in the tie, however neither country can make Saturday's Hopman Cup final after the Ukraine secured top spot in Group A early on Thursday with a win over Australia Gold.
Share
