Cork were criticised for falling away against Kilkenny in their previous outing but had eight points to spare over the Déise in Walsh Park last Sunday, with Lehane chipping in nine points.
“We tried to maintain our attitude for the second half, we did that for the first half against Kilkenny only, and knew we had to do it again this time for the whole game, particularly with the wind being so strong.
“We know we have the hurling, the skills, and the fitness will always come with training, but mentality is huge against teams which have done well.
“The second half was huge, we were really aware of it and zoned in on it, and when it works out it’s great because you know then that you can do it.
“Waterford are so well organised as a team, they play so well together that you have to crowd them, and sometimes that works out, and Sunday it did.
“Not being disrespectful but it is the league, there’s a long year ahead yet. We’ve to take it game by game.”
Lehane added that Cork would take confidence from the victory: “This was a really important game, especially last year with the league the way it went.
“And it was an important game to respond to, when you are under pressure, those are the main games to respond to, to show we can do that.
“Obviously, the first game was important in the league, just to get a win under the belt but when the stuff hits the fan, and you are able to respond to that and get a win, that is much more encouraging and that is when you get more confidence.”
Lehane was modest about his own contribution, which included seven points from frees: “There was the one that hit the upright from the 20-metre line but I’d blame the wind. Hoggy (Patrick Horgan) I know is an incredible free-taker and they are just passing it around a bit for now, trying a few different things.”
The Midleton man said the competition in the Cork hurling squad for places means “there are no guarantees” for starting places.
“Yeah, that is what we are looking at, to have competition for places in the squad and make sure there are no guarantees for players to be on the team. That is what we are building towards and you saw how the younger guys performed today.
“Maybe we didn’t have that competition in the last few years, but it is certainly keeping everyone on their toes.”
Tipperary’s visit to Pairc Ui Rinn rounds off the Rebels’ league programme.
“That’s still two weeks away,” said Lehane.
“We have a week off next week and we will just take on what we learnt today and forget about it.
“This game is in the past now, it is done and we just have to look forward to the next game.”