The Ghanaian lasted the entire duration as the Eagles claimed a crucial 1-0 win at Selhurst Park.
Troy Deeney's own goal on 68 minutes was the separating factor.
"It was a difficult one," Schlupp told Palace TV.
"We knew what was going to come from Watford. We knew it was going to be a physical game.
"I think we deserved that win, created some chances and it was a bit unfortunate for them with the own goal, but it was always coming from us."
Palace consequently sit two places above the relegation zone on 16th position.
"Their gameplan might have been to try to lock off our wingers, they would know how dangerous they are," Schlupp added.
"Wilf [Wilfred Zaha] and Andros [Townsend] do a great job taking on their full backs and stuff, so I don't think that gameplan really worked out too well.
"You've got to give us credit, that's another clean sheet and another win, so now I'm just looking forward to that next game."
Schlupp joined the Eagles on a four-and-a-half-year deal from Leicester City in January.
Saturday's game was his sixth league appearance and second start for Sam Allardyce's men.