The former Manchester United goalkeeper was the Baggies' star player, keeping a clean sheet and saving a Steven Gerrard penalty, before Gareth McAuley and Romelu Lukaku hit late goals.
West Brom had not won a game in 2013, despite putting in some good performances, and the 29-year-old shotstopper believes the result was a great way to end the club's poor run of form and could prove to be a turning point in their season.
"Today could be a turning point for us," Foster told Sky Sports. "We haven’t had the best of times recently so it was important to get a result today if we could.
"We’re just taking it one game at a time, but we’re obviously pleased with tonight at Anfield.
"It’s great to be back up above Liverpool, we’re not really looking at other teams but after the run we’ve been on it’s a great feeling.
"We needed that [win], we have been on a poor run, performances have been decent. We knew if we kept our performances up we’d always have a chance."
Foster came up big with a diving save on Gerrard's penalty, diving to his left and extending his arm low on the ground after Luis Suarez had controversially earned the spot kick.
"I did know a little bit where Gerrard was going to go [when he took the penalty]," Foster said. "I had a look before the game and knew to go the left hand side, but I also went with my instincts on it. It was an important save at an important time."
McAuley was also delighted with the team's display but believed that the Reds' penalty given against defensive partner Jonas Olsson, should not have been awarded.
"I thought the pen was a bit harsh but he gave it but Ben saved it so that’s great," the said McAuley, whose header off a corner kick gave West Brom the lead. "I’m always delighted to score, it was an important goal at an important time."