"I haven't played in the darkness or under the lights in a very long time and I felt like my rhythm was off on serve, my timing a little bit". Particularly when he was failing to convert any of the five match points he held while serving for the win at 5-4 in the final set. "I just fought and tried to make it tough for him", Murray was quoted as saying by the ATP World Tour's official website. "If I stay fit and healthy, I'm not anxious so much about ranking".
Murray had surgery on his right hip in January, only returning to action on June 18, facing Nick Kyrgios at Queen's. Murray, whose best Washington finish was a runner-up effort in his 2006 debut, served for the match in the 10th game but squandered five match points, four of them on errors, and McDonald broke back to 5-5 when Murray netted a forehand to end the 12-minute game. The fifth will come in the second round at Washington against Kyle Edmund, the man who overtook him as Britain's top-ranked man during Murray's injury absence. There was still another match left to go in the main stadium, and it involved another three-time major champ: Stan Wawrinka, who faced American qualifier Donald Young. I want to be winning matches and competing against the best players and that will build my fitness up quicker than anything I could do in the gym. The world number 198 had a first-round match against United States qualifier Donald Young rained out.
One of Murray's four first-set double faults surrendered a break in the third game and Murray's seventh consecutive lost second-serve point gave McDonald a 3-2 edge when the American hit a forehand victor.
The Edmund clash will happen if former Wimbledon champion Murray comes through his opening test. Edmund, who has replaced Murray as British number one, receives a bye to round two.
But Murray drew things level, taking a crucial game nine in the second for a 5-4 lead and serving out the set.
Tunisia's Malek Jaziri booked a second-round match against third-ranked defending champion Alexander Zverev of Germany by defeating Russian Evgeny Donskoy 6-4, 6-1.
Murray, 31, converted his seventh match point after more than two-and-a-half hours on court against the American. There was a cross-court passing victor at just the right angle.