Andy Murray knows he must start finding first serves on a consistent basis if he is to keep alive his hopes of winning the Barclays ATP World Tour Finals on home soil at London's O2 Arena.
The British number one described his serving as "pants" following last night's 3-6 6-3 6-1 defeat by Roger Federer, in which he registered with his first delivery only 45 per cent of the time and hit two games' worth of double faults.
Murray would have booked his place in the semi-finals with a victory over the world number one - and the result ensured Federer will definitely finish the year on top of the rankings - but instead he goes into tomorrow afternoon's clash with Fernando Verdasco knowing even a win could see him go out if Juan Martin del Potro beats Federer in the evening match.
Of his performance last night, he said: "I just didn't feel like I played well. If you give someone the opportunity to dictate, not only on his own service games but on yours, it's very difficult to win.
"I served so poorly that anyone would have looked good against me because you get a chance pretty much every single point."
Murray has beaten Verdasco in seven out of the eight matches they have played, including on his way to the title in Valencia earlier this month, although the one time the Spaniard did come out on top was in arguably the most important clash at the Australian Open in January.
Looking ahead to tomorrow, he continued: "Against all the guys in the group I've got a good record. If I play well, there's a good chance I win. If I don't, then there's a good chance I lose."
Last night's match was the biggest of the tournament so far and a capacity 17,500 crowd certainly made themselves heard. A large proportion were cheering for the Swiss rather than the Briton - which was only fair, according to Murray.
"I thought the atmosphere was great," he continued. "To play in front of a crowd like that's awesome. Roger's record at Wimbledon, what he's done in tennis, he deserves support everywhere he goes."
After cementing his position ahead of Rafael Nadal in the rankings going into next season, Federer reflected on a golden year that has also seen him complete a career grand slam, pick up a record 15th major title and celebrate becoming a husband and father.
"That was one of my big goals for this season," he said of his return to the top of the rankings. "And it's one of the greatest performances I think I've achieved.
"Seeing also what happened off the court: getting married, having twin girls, reaching all four major finals. Playing so well at the most important moments, it's been the key this year, and staying healthy.
"Especially after having a rough 2008, coming back this year and being able to dominate and play at the top when the depth in tennis is so, so great at the moment. I think it's a wonderful achievement. It's a wonderful feeling."
In the day's first Group A match, Del Potro edged past Verdasco 6-4 3-6 7-6 (7/1) in a nervy encounter.
Today's Group B action sees defending champion Novak Djokovic take on Robin Soderling before Nadal aims to post his first win of the tournament against Nikolay Davydenko.