Danny Ings gave Southampton a first-half lead as Spurs failed to register a shot on target in the first half.
"They came at us and pushed hard first half," Bale told Sky Sports. "We have only had a couple of days with the new manager to try to do a couple of things.
"We have only had a couple of days with the new manager so it will take time. We had a good chat at half-time. We had a few positional issues and needed to be more patient. It was a very good team talk at half-time.
"We came out in the second half, we controlled the game second half and deserved the victory."
Asked afterwards what he said, Mason told reporters: “It was just about giving them the belief and the bravery to play and express themselves."
Bale would not be drawn on whether he should remain in the side for the Carabao Cup final.
He said: "I know everyone talks about me a lot but it really isn't about me. I don't care about me. I just care about Tottenham.
"It was important to get the win. It gives us a chance of the top four and we will fight until the end."