Commanche Falls swooped to conquer his Unibet Stewards' Cup opponents at odds of 10-1.
Michael Dods' sprinter burst from the pack up the stands side to defeat fellow fast finisher Gulliver (18-1).
Until half a furlong from home, the group of runners nearest the crowd looked to be facing a losing battle against those on the far side, as William Buick made the best of his way home on Great Ambassador (8-1).
But the well-backed runner had no answer to the finishing kick of his two rivals and had to settle for third. Rank outsider Total Commitment (66-1) took fourth.
"Every time he comes to a gig he keeps putting up his best performance ever," said Commanche Falls' jockey Connor Beasley.
"The ground was a question mark today but I knew once I got him rolling, he'd pull out all the stops."
The start of the race was delayed after Zarzyni broke out of the stalls and ran loose, which led to the field having to be taken out of their starting berths and reloaded.
Earlier Wonderful Tonight (4-5f) justified her short odds in the Group 2 Qatar Lillie Langtry Stakes.
David Menuisier's filly raced keenly enough in the closing stages and had to be driven out by Buick, the meeting's top jockey.
"I know she has won over this trip before in Paris last year, but I think she's a bit speedier now. She doesn't need to be running over this trip again," Buick said.
“To be honest, she races how she always does. She's energetic and I was delighted to get a lead on her. We went slow and she took it up a fair way out but has stuck on all the way to the line."
Wonderful Tonight's odds for the Arc in the autumn are unchanged at 8-1 with Paddy Power.
Results from Goodwood on Saturday
1.20
1. Oo De Lally 10-1
2. Seven Brothers 25-1
3. Shark Two One 20-1
1.55
1. Mr Wagyu 16-1
2. Able Kane 33-1
3. Power Over Me 9-1
4. Music Society 13-2
2.30
1. Prince Alex 13-2
2. Urban Artist 9-2f
3. Future Investment 7-1
3.05
1. Wonderful Tonight 4-5f
2. Tribal Craft 16-1
3.40 Unibet Stewards Cup
1. Commanche Falls 10-1
2. Gulliver 18-1
3. Great Ambassador 8-1
4. Total Commitment 66-1
4.10
1. Imperial Fighter 9-1
2. Ring Of Beara 3-1
3. Capital Theory 22-1
4.40
1. Rebel Territory 7-2f
2. Sweet Reward 14-1
3. The Whipmaster 6-1
