Most players would cite their coach as the most important person to have alongside them on tour but for Sam Querrey his chiropractor is equally significant.
The big American with the big serve has his chiropractor travel with him every week on tour to help protect his biggest asset. It's a relationship that started last June and has been a big part of Querrey's resurgent form on the men's tour.
He started last year ranked 93 in the world and even resorted to lower-level Challenger tournaments for a short time as he worked to find the sort of form that saw him as high as No17 in the world in January 2011.
Until June, his record was 13 wins and 14 defeats but that improved dramatically in the second half of the year and he won 24 of his 35 matches in that period to climb up the rankings to his present position of 22. He picked up his seventh career title and made the semi s of three other tournaments.
It's likely his chiropractor enjoyed a good take of the winnings.
"That was a huge part of it," Querrey admitted of his turnaround. "I think starting in Queens, that was where I started playing well. I made the semifinal and won two rounds at Wimbledon. It was the first time I made a semifinal in a year. I got my confidence back after Queens and Wimbledon. [I then] went into LA and won that and it just kind of kept rolling from there. Having Casey [my chiropractor] there was a huge part."
The fourth seed fired down another 14 aces yesterday in his 6-4 7-6 defeat of Canadian qualifier Jesse Levine and will now take on second seed Philipp Kohlschreiber.
"He's a big guy," Kohlschreiber said. "He serves well and if he is confident he is very tough to beat. They are fast conditions so they will favour his game a little bit more, but I will try to hang in, to return pretty well. That's the key, that I play good return games. If he serves well, you cannot do too much."