Japan's Kei Nishikori inched closer to his first masters championship on Friday, with a 6-4, 6-7(1), 6-3 quarterfinal win over Croat Marin Cilic.

Cilic, who had won both of their two career finals, including the 2014 U.S. Open, had not lost to Nishikori since the 2015 Japan Open, but has now lost both their matches on clay. But this one was not easy despite Cilic hurting his right leg. The Croat rallied and fended off three match points before finally succumbing in the final set.

"It was a long match and I found it hard to maintain my concentration," Nishikori said after the 2-hour, 55-minute clay-court clash. "In the third set, although he put me under pressure, I was able to bear down and concentrate in the final two games."

"All my matches here have been played at a high level, but I still have corrections to make and I'm getting better little by little."

Nishikori, ranked 36th in the world due to a wrist injury that prevented him from playing for roughly five months, was extremely composed at the start of the match, rarely missing his shots. But the Japanese star faltered when Cilic was hurt and on the ropes in the second. Despite having an issue with his right thigh that required a medical timeout and temporarily limited his mobility, Cilic became more focused and intense.

When he had the chance to put his opponent away, Nishikori couldn't get his first serves in and failed to convert three second-set match points before missing nearly every shot in the tiebreak. Nishikori finally put Cilic away in the eighth game and clinched it with a strong serve on his fourth match point of the afternoon.