Goals in either half from Demba Ba and Willian earned Chelsea the win at Anfield, which lifts the Blues to within two points of their opponents, with Manchester City sitting third, six points off Liverpool, with two games in hand.
Chelsea appeared out of the title race after losing 2-1 at home to Sunderland last week, but this win has reinvigorated their title chase.
Lampard told Sky Sports News: "It wasn't mathematically impossible before today and certainly not now. We'll keep going. We showed that desire on the pitch.
"We were devastated last week against Sunderland because it was a home game and we wanted to win. But we've bounced back today.
"We changed the team, Tomas Kalas came in for his debut and was absolutely fantastic. Every man out there was brilliant."
Ba's goal came after a slip from Steven Gerrard, who has been instrumental in Liverpool's climb to the top of the table.
Lampard had sympathy for his England team-mate, saying: "Of course. It can happen to any player. Whether Liverpool go on to win the league or not, this doesn't take anything off the player he is and has been. He's been driving them all season. It's not a nice moment."
Lampard also dismissed criticism of Chelsea's defensive tactics.
"That's the way the game is," he said. "We played to win the game. We've won titles before, we know what it takes.
"If we're going to go away and dig in to win games, that's what we'll try to do. Against Liverpool at home earlier in the season we were fantastic going forward. If we can do that, we'll do that. You have to have both sides to win the league."
Ba has been a bit-part player this season, but it was his third crucial goal in recent weeks after he also sent Chelsea through to the Champions League semi-finals with a strike against Paris St Germain, while netting the winner at Swansea.
He said: "I got this chance, I had to take it and I took it. As a striker you always have to be ready.
"Sometimes you have a lot of chances and sometimes just one chance. We are very happy."