The American, 25, beat unseeded Russian Anastasia Pavlyuchenkova 2-6 7-5 6-1 in two hours and 16 minutes in Melbourne.

Collins broke twice in the second set and won seven games in a row as she raced through the decider.

The world number 35 faces two-time Wimbledon champion Petra Kvitova or 15th seed Ashleigh Barty next.

"It was my first time playing on Rod Laver and I didn't even practise on here before so it was quite the experience," said Collins. "I absolutely loved it."

It was a feisty match from the start as the opening two games lasted 22 minutes and saw seven break points - including five which Collins could not take.

Collins, who knocked out world number two Angelique Kerber in the fourth round for the loss of just two games, was vocal throughout and showed plenty of emotion on court.

Pavlyuchenkova's experience of four previous Grand Slam quarter-finals was evident in the first set as she remained calm and held off Collins' early pressure.

The Russian, who beat 2017 US Open champion Sloane Stephens in a mammoth fourth-round tie that went on until 01:53 local time, fought back from 5-2 down in the second set to 5-5. But she had the stuffing knocked out of her when Collins broke again to level the match.

The American was full of momentum and went on to break twice in the final set, while Pavlyuchenkova won only nine points on her serve in the decider.

Collins could not convert a match point at 5-0 and was made to work in her last service game before she eventually secured victory on her third match point.