Recently, when the lights go on, Roger Federer's game has disappeared.

Which is shocking for a player that has been as successful as he has.

Tennis.com reported that Federer, the current No. 5 player in the world who still holds the record for most weeks spent at No. 1, blamed his quarterfinals loss to Kei Nishikori at the Sony Open on his struggles to play during nighttime.

Federer, who had lost 18 points total on serve in his first three matches in Miami, served at just a 53 percent rate on his first serves against Nishikori. Despite leading by a set and up a break, Federer's serving inconsistency led to his 4-6, 7-5, 6-4 defeat.

"I just couldn't find my rhythm on the serve (against Nishikori), which was surprising especially after how well I played and served specially this week," Federer said after the quarterfinal loss. "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."

According to tennis.com, Federer lost to Tomas Berdych in 2010 and to Andy Roddick in 2012 - both matches played at night.

"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."

He said his inability to find consistency on his server, especially the slider wide on the deuce court, led to him losing confidence in his forehand.

"Then because of my serve" Federer said, "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."

Federer didn't sound the alarm about his play at night during other events, but he needs to do something to make sure that lack of confidence doesn't creep into other night matches. During his 2014 resurgence, Federer has split matches with No. 2 Novak Djokovic, who toppled No. 1 Rafael Nadal in straight sets in the Sony Final.

Federer still is harboring thoughts of returning to No. 1 but his play at night suggest his shot at Nadal's standing may be a shot in the dark.

Do you think Roger Federer's play at night is something that could derail his comeback? Comment below or tell us @SportsWN.