Grigor Dimitrov has been praised after his gutsy Miami Open quarter-final win over Francisco Cerundolo

Speaking on Sky Sports’ coverage, Martina Navratilova said: “He was running on fumes at the end of the second set.

“What an amazing effort from Grigor. He was down and just kept coming back. Cerundollo looked much less tired and I would have backed him to win, but Grigor did it.

“I’ve never seen a player collapse after the match they have won. The fact that he was still able to win when he was feeling this lousing was an amazing emotional and physical effort.

“At least he has got a day off to hopefully recover. He probably won’t be playing tomorrow and will just do some light bike work to get the blood flowing.

“It was amazing that he was able to play this well when he felt so lousy about his prospects.

“It is a good thing that we have tie-breaks in the final set because one or both of them would have been taken out of here on a stretcher.”