What led to Dimitrov's exit from Australian Open

A back spasm left Grigor Dimitrov unable to put his socks on, let alone pull them up, on Tuesday as the struggling Bulgarian exited the Australian Open quarter-finals with a 2-6, 6-4, 6-1, 6-2 defeat to qualifier Aslan Karatsev.

The 18th seed, who had raced through the first four rounds in Melbourne without dropping a set, took a medical timeout after losing the third set but it did little to improve the situation.

"I just got a back spasm yesterday, and that was it," Dimitrov said. "We couldn't fix it on time. It happened early in the match and kept progressing. It was unstoppable."

"I couldn't put my socks on before the match, so I knew it was going to be tough. I tried, but it wasn't good enough."

Dimitrov, who earned the nicknamed 'Baby Fed' as a junior due to similarities between his game and Roger Federer's, is the latest player to be hit by injury in Melbourne with both Matteo Berrettini and Casper Ruud pulling out of matches on Monday.

Novak Djokovic and Rafa Nadal have also struggled with physical issues but remain in the tournament.

"I'm just going to take the positives out of this situation," said Dimitrov. "What happened, happened. I need to swallow it. But I'm not just going to keep my head down..."

"Today was just bad luck. That's what it is. Someone had to win, and this was his day. Clearly I'm frustrated, but I don't need to dwell on it."

"All I can do is draw the positive out of it, get some days off, figure out the next move, and get back on the horse."