Cilic through at Wimbledon as injured Nishikori retires

Marin Cilic was handed the easiest of fourth-round victories at Wimbledon as Kei Nishikori retired due to a rib injury.

Monday's second match on No. 2 Court looked set to prove an intriguing one, with the two finalists from the 2014 US Open, won by the Croatian, looking to seal a place in the last eight.

However, it soon became apparent that fifth seed Nishikori, who had been hampered by a rib injury sustained at Halle ahead of this tournament, was well short of full fitness as Cilic raced through the first set in just 16 minutes.

"It started in Halle.  It's the same injury that I had it in first match in Halle.  It's not been recovering well these two weeks," Nishikori said.

"After the third round, it's got worst, so I was hoping to get better, but it was too much pain on the court. I couldn't really compete.

"I was thinking about it in the second set.  Even before the match, I knew it's not going to be easy for me to play, you know, hundred percent.

"Also Marin was playing great on the court. Every point I played it go worse. I didn't want to, but I guess, yeah, I had to retire today."

The Japanese initially battled on, his serving speed severely limited, before retiring with Cilic holding a commanding 6-1 5-1 advantage.

Cilic, the ninth seed at the All England Club, will now face seven-time champion Roger Federer in the quarter-finals, with the Swiss having beaten Steve Johnson in straight sets on Centre Court.