Chawla hit an unbeaten 102 and took eight wickets on his Sussex debut
Leg spinner Piyush Chawla took 6-152 as Sussex completed a 10-wicket victory over Worcestershire at New Road.
The home side began day four on 120-3, 212 short of avoiding an innings defeat but saw Daryl Mitchell and Moeen Ali boost their chances of saving the game.
Mitchell (99) and Moeen (124) added 208 for the fourth wicket, a record against Sussex, but Chawla kept chipping away as Worcestershire were all out for 392.
Michael Yardy and Chris Nash knocked off the 61 needed to win with ease.
But the match really belonged to Chawla, who only signed for Sussex on the morning of the match.
He took 2-89 in Worcestershire's first innings, but marked his arrival in England in style with an unbeaten 102 in Sussex's innings.
And his second innings heroics with the ball not only condemned Worcestershire to a fourth defeat in five Championship games and gave Sussex their first win, but also made him the first player to score a century and take five wickets in an innings in four-day cricket this summer.
Sussex had to wait for their breakthrough as they pushed for victory, Moeen gloving a leg-side catch off James Kirtley to end his 205-ball vigil.
It proved vital as Chawla got to work, taking three wickets for seven runs in 13 balls.
First Mitchell edged to Ed Joyce to end his vigil, before Ashley Noffke was trapped leg before.
Gareth Batty swiftly followed when he swatted a catch to Kirtley.
Steve Davies (35) and Kabir Ali added 39 but both fell in quick succession to leave Worcestershire 346-9, only 14 in front.
Chris Whelan (24) and Matt Mason (22 not out) added 46 for the last wicket but they could only delay the inevitable as Sussex reached their target with an hour's play left.
Worcestershire's director of cricket Steve Rhodes told BBC Hereford and Worcester:
"We had four or five lbw decisions that went against us and that's a quarter of your 20 wickets that you lose in the game.
"You could easily say 'that's Steve Rhodes moaning about the umpires' and I don't want to do that.
"The bottom line is that if you look at Sussex and you look at Worcestershire in those four days, they batted, bowled and fielded better than we did and deserved to win."
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