Updated

Memphis, TN (SportsNetwork.com) - Reigning champion Kei Nishikori was a come-from-behind quarterfinal winner Friday at the U.S. National Indoor Championships tennis event.

Seeded No. 1 at an ATP event for the first time in his career, the rising Japanese star fought back to beat Russian Alex Bogomolov Jr. 3-6, 6-3, 6-2 in 2 hours, 18 minutes on Day 5 at The Racquet Club of Memphis.

"It wasn't easy today," Nishikori said. "My tennis level is not quite 100 percent yet, so I hope I can get better. I have a lot of confidence and my goal is to win the tournament."

Nishikori topped Spaniard Feliciano Lopez in last year's Memphis finale.