The midfielder, who scored the winner in fine fashion with a signature free-kick, helped Saints move to within two points of 17th placed Everton.
"Massive win," Ward-Prowse reflected. "I think this period in the season is pivotal for us. It started last week with an important point away at Arsenal and we knew we could follow it up today.
"To come from 1-0 down is very difficult in any Premier League game, but it shows the togetherness of the team and the belief in what we're doing. We could see that tonight for sure.
"I think we dominated the game, but were a bit sloppy in places. That happens when you're under pressure. We trusted each other and maintained our belief, which is so important.
"The lads who came on made a real difference for us as well. Getting back into the game was important. You could feel the energy in the stadium really pick up after we scored.
"I was feeling confident before the free-kick. I spoke to Sofiane before and said 'this is mine'. He left it to me, and thankfully it went in."