Roger Federer expressed surprise at his serving struggles during his quarterfinal loss in Miami to Kei Nishikori, also noting that he has often had problems at night during this tournament.
Federer had been dominant on serve during the early rounds, dropping just 18 points in three previous matches. Against Nishikori, his first-serve percentage was 53 percent, with Federer winning 70 percent of his first-serve points and 48 percent of his second-serve points. During the first set, which Federer won, his first-serve percentage was 37 percent.
"I just couldn't find my rhythm on the serve today, which was surprising especially after how well I played and served specially this week," he said after the match. "I think it didn't 'take off' the way it did during the daytime -- you could expect that, but then plus the temperature drop had something to do with that.
"In the dark for some reason, I haven't played many matches this year."
Federer, a two-time Miami champion, agreed that he has frequently had difficulties in night matches during the event. He lost under the lights to Tomas Berdych in 2010 and to Andy Roddick in 2012, with an afternoon defeat to Novak Djokovic in between.
"Here in the night I have struggled in the past. I don't know exactly what it is," he said. "But I have played a lot of frustrating matches like the ones I have played here tonight and also in previous years.
Though Federer led by a set and a break twice in the second set, Nishikori prevailed, 3-6, 7-5, 6-4.
"He right away made me feel uncomfortable and stayed with me, so he was more consistent in the second and third, and those are the ones he won," said Federer.
"I think the biggest problem today was I couldn't get my serve going ever, especially the slider wide on the deuce. That's what's been working so well for me at this tournament. I was looking for it time and time again, I was missing it.
"Then because of my serve, I started questioning a bit on my forehand, a bit of my backhand -- 'what am I supposed to do,' here I am now going over so many second serves, which I didn't have to do at all in the first three matches...I couldn't quite react to it."