MEMPHIS (AFP) - Top seed Kei Nishikori kept his bid for a third straight ATP Memphis title alive on Friday, with a 4-6, 6-3, 6-4 quarter-final win over Austin Krajicek.

The 25-year-old Japanese star, ranked fifth in the world, needed 2hr 10min to subdue the American qualifier, ranked 156th.

Nishikori seized control in the third set with an early break for a 2-0 lead.

Krajicek broke to level the set at 4-4, but Nishikori immediately broke back to avert the danger and served out the match.

Nishikori, who saved eight of the 10 break points he faced, next faces the winner of Friday night's match between third-seeded John Isner and fellow American Sam Querrey.

Second-seeded South African Kevin Anderson also advanced, downing American Steve Johnson 6-4, 6-4.

Anderson fired 16 aces and saved all three break points he faced in the 65-minute contest. He will take on American Donald Young, who defeated Australian Bernard Tomic 7-6 (10-8), 4-6, 7-5 to reach the semi-finals.

"I got a little nervous there at the end, but I was happy to come through," said Young, who reached the fourth ATP Tour semi-final of his career. "Any time you make the weekend, you're playing well. I made the weekend. It hasn't happened too often in my career, so when it happens I'm very excited."