US Open 2018: Rafael Nadal through after David Ferrer retires injured

Ferrer was a break up in the second set having lost the opener but was clearly struggling with a left calf injury and decided he could no longer continue

Nadal is safely through to the second round (Getty Images)

Defending champion Rafael Nadal reached the second round of the US Open in unfortunate circumstances with opponent David Ferrer forced to retire during his final grand slam match.

The 36-year-old, one of the outstanding players of this era, is renowned as a warrior and had never pulled the plug midway through a contest in 207 previous grand slam matches.

He was a break up on Nadal at 4-3 in the second set having lost the opener 6-3 in steamy conditions on Arthur Ashe Stadium but was clearly struggling with a left calf injury and decided he could no longer continue.

Ferrer plans to retire at an event in Spain next season, and he told the crowd: "It was pain. I tried to play but I think it (his calf muscle) is broken. I have really good memories here. This is my last grand slam. I'm so sorry because I can't finish the match. I will miss you a lot."

Ferrer was forced to retire midway through the second set (EPA)

After a fine start to the match, Nadal's forehand went awry in the second set, but his primary feeling at the end of the clash was empathy for his compatriot.

The world number one said: "I'm very, very sorry for him. He's one of my closest friends on tour. We shared amazing moments together playing French Open finals, a couple of Davis Cup finals. It's sad to see him finish like this but he deserves everything because he's a fantastic player."

Ferrer reached his only slam final at Roland Garros in 2013 and climbed as high as world number three the same year.

Nadal moves through to a second-round clash with Canada's Vasek Pospisil while Stan Wawrinka is also on an eight-match winning streak at Flushing Meadows after defeating Grigor Dimitrov for the second successive slam.