Madison Keys’ remarkable journey through the Australian Open will continue into the semi-finals after she conquered Venus Williams and a leg injury on Rod Laver Arena.

Keys won 6-3 4-6 6-4 in a roller-coaster quarter-final despite suffering a groin injury midway through the all-American showdown.

The 19-year-old took a lengthy injury time-out trailing 1-4 in the second set and looked as though she may not be able to continue.

But Keys emerged to push the veteran 15 years her senior to a third set, won with power and poise.

The unseeded teenager had never before won more than two matches at a major from 10 attempts but now finds herself in the last four at Melbourne Park.

The world No.35 is the lowest ranked player left in the draw, but would have the rest of the field worried after powering 34 winners to Williams’ 10 to march on after one hour and 55 minutes.

“I’m happy that my leg didn’t prevent me from having a win,” Keys said.

Keys looked overcome at her achievement after calling the Williams sisters her inspiration for taking up tennis.

“The moment is definitely sweeter by being able to play Venus,” she said.

“It’s amazing, you just have to embrace the moment.

“Now I get to enjoy another moment next round.”

Serena Williams looms as her next opponent, as the world No.1 takes on 11th seed Dominika Cibulkova in Wednesday’s second quarter-final.

The biggest challenge for Keys looks to be overcoming her leg injury, which she confirmed was the same strain that forced her withdrawal from Wimbledon last year.

There is certainly no problem with her power game, which was in full song in the first and third sets.

Pushing and bullying her around the court, Keys broke Williams at 3-3 to seize the momentum.

The teenager consolidated and broke again to win the set 6-3 in just 29 minutes.

Life returned to Williams’ campaign through Keys’ injury as the veteran surged to a 4-1 lead.

Coach Lindsay Davenport watched on the stands with an agonised face as Keys grabbed her groin after points and struggled to move freely.

Keys returned from the locker-rooms to break Williams to love and level the second set at 4-4.

While losing the second set 6-4, Keys re-found her range and blasted home with 14 third-set winners.

Williams praised Keys for her tenacity.

“In this kind of match you have to be aggressive,” she said.

“All credit to her.”