MEMPHIS (AFP) - Two-time defending champion Kei Nishikori rallied to get past US qualifier Ryan Harrison on Wednesday to book his quarter-final spot at the ATP Memphis Open.
The Japanese top seed, who reached the quarter-finals of the Australian Open in January, gained a key early break in the third set and secured the 3-6, 6-3, 6-4 win on his fourth match point.
"It was a tight game but I'm really happy to win," the 25-year-old said.
"I think it's important to win something like this sometimes, it's good for confidence."
Nishikori, who enjoyed a first-round bye before opening his title defence against Harrison, said he feels like Memphis is "becoming my tournament".
Still, he said he will have to play better in the quarter-finals where he will face another American qualifier, Austin Krajicek.