The Potters sat above Ronald Koeman’s men heading into Saturday’s game at the Britannia Stadium, but two goals from Graziano Pellè helped Saints to a 2-1 win against Mark Hughes’s side.
Now, with Liverpool next – a side who Saints also moved above thanks to Saturday’s win – Ward-Prowse says momentum could prove crucial over the remaining games of the season.
“I think it was an important win. We had a good run of six games and then had the two games where we were disappointed with how we played,” Ward-Prowse told reporters.
“This is a real good three points that have put us back on track. It has also put us ahead of one of our rivals for what we want to achieve.
“To be able to get one over them gives us a bit more momentum over the next few games.
“But these three points won’t mean anything if next weekend we go and lose to Liverpool,” Ward-Prowse continued.
“That’s a game that all the fans want to win and of course we want to win.
“I think if we win that, that really does give us more momentum going into the final leg.”
Skipper José Fonte will be available for that clash with Liverpool after missing the trip to Stoke City through suspension, but Ward-Prowse was pleased with the way Saints dealt with his absence.
“It’s a massive well done,” he added. “He’s our leader and I think the way the lads at the back stepped up was fantastic.
“He’s obviously an important personality. It’s a good sign that we can cope at tough places like Stoke.”