Jannik Sinner said he could not accept his progress to the Wimbledon quarter-finals "as a win" after a tearful Grigor Dimitrov was forced to retire in an emotional end to their match.

World number one Sinner was staring at the prospect of a shock defeat as he trailed Dimitrov by two sets when the Bulgarian 19th seed dropped to the floor in pain.

The 34-year-old Dimitrov, who has now been forced to retire in each of his past five Grand Slam appearances, clenched his right pectoral muscle and could not continue following a short medical timeout.

Italy's Sinner, a three-time major winner, has become only the ninth man in the Open era to reach seven consecutive Grand Slam quarter-finals.

But that was not an achievement he felt that he could celebrate on Centre Court on Monday night, instead concerned only with his friend's wellbeing after a heartbreaking conclusion.

Sinner, who reappeared for his on-court interview after assisting a devastated Dimitrov off the court, said: "I don't take this as a win at all, this is just an unfortunate moment for all of us to witness.

"He has struggled in the last Grand Slams with injuries a lot, so seeing him again with this injury is very tough.

"We all saw by his reaction how much he cares about the sport. He is one of the hardest-working players on tour and it is very unfortunate."

The 23-year-old added, before calling on the crowd to join him in applauding Dimitrov and his team: "This is not the end we wanted to see and it's very sad. We all wish him only the best."

Sinner, himself hampered by an elbow issue following a fall earlier in the match, looked set to be on the receiving end of a huge upset as he trailed 6-3 7-5 2-2 after two hours.

It came after his record-equalling start to the tournament, in which he lost just 17 games across three impressive performances - the joint-fewest in the Open era.

He would have set another record had he lost no more than nine games to Dimitrov - but his inspired opponent, who has reached eight major quarter-finals, had surpassed that total midway through the second set.

But, 12 months after he retired from his fourth-round match against Daniil Medvedev at the All England Club because of a knee injury, Dimitrov reappeared from his medical timeout in tears knowing his tournament was over.

"I don't know what to say because he is an incredible player and we all saw this today," said Sinner, who will play American 10th seed Ben Shelton next.

"He has been so unlucky in the past couple of years. He is a good friend of mine and we understand each other very well off the court too.

"Seeing him in this position, if there was a chance for him to play in the next round he would deserve it.

"Mostly, I hope he has a speedy recovery."

Sinner later added in his news conference that he will have an MRI scan on his elbow on Tuesday "to see if there's something serious".