A Erhun Oztumer brace saw Walsall end a six-match winless run in all competitions with a 3-0 League One victory over Doncaster Rovers.
The lively midfielder scored twice in a four-minute spell to come back to haunt Darren Ferguson, who managed him at Peterborough United.
And substitute Kieron Morris added a third late on.
It came as a shock to the system for a Doncaster side that had dominated possession in the first half.
Ben Whiteman missed a good chance but Rovers should have been ahead just before the break. Tommy Rowe hit the post with a low shot before Marquis fired the rebound wide with the goal gaping.
The hosts were punished in the second half. On 62 minutes, Tyler Roberts pinched the ball away from Joe Wright and squared to Oztumer, who slotted in from close range.
And after 66 minutes the lead was doubled when Joe Edwards found Oztumer in space to fire past Ian Lawlor.
The game was put to bed with 10 minutes remaining when Amadou Bakayoko latched onto a long clearance and slid in a pass for Morris who finished well.