Hewson birdied the first extra hole after the pair had finished tied on 11 under par following an extraordinary finish to the final round at Golfpark Holzhausern.
Hewson slam dunked a bunker shot for an eagle on the 17th and then birdied the last to overhaul Ireland's Lauren Walsh, who had set the clubhouse target of 10 under following a brilliant 64.
Malik then amazingly also holed out from the same bunker on the 17th for eagle and matched Hewson's birdie on the last to force a play-off, which the Englishwoman wrapped up in style with another birdie.
"I'm a little bit lost for words really," said Hewson, whose previous win came in the Investec South African Women's Open in 2020.
"Huge congrats to Tvesa as well. It was an unreal finish from her today. It was an honour being out there with her in the play-off. It feels a bit surreal. It's been a while since I've been in this situation.
"Coming from my first-ever event on Tour [which I won], to now, it's been a journey. A lot of ups and downs. I'm lost for words."
Kelsey Bennett, who finished six shots off the leaders in joint 19th was the highest placed Australian with Kirsten Rudgeley joint 34th and Whitney Hillier 56th.
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