Roger Federer is through to the semi final stage of the Australian Open after a drama-filled quarter-final match.

The Swiss saved seven match points against American, Tennys Sandgren as he prevailed 6-3 2-6 2-6 7-6 6-3 in an epic encounter on Rod Laver Arena.

The world number three struggled with an apparent groin injury as Sandgren threatened to beat him and reach a first major semi-final, but Federer’s struggle paid off in the end.

“I don’t deserve this one but I’m standing here and I’m obviously very, very happy,” he said in the post-match on-court interview.

“I just said ‘I believe in miracles, there could be rain … I don’t know'”.

“It wasn’t bad enough where I thought it was going to get worse, it was just stiff and tight. [So I thought] just let him finish me off in style. I was incredibly lucky today.”

Federer, whose last grand slam title came in Melbourne in 2018, is vying to win the Australian Open for the seventh time.