Neil Harris praised the impact of Tom Elliott as the striker marked his full debut with a brace to help Millwall beat Stevenage 2-0.
Elliott's second-half headers were enough for the Lions as they progressed to the second round of the Carabao Cup.
Despite a sluggish first half from the home side, Harris revealed he did not go to town over their performance at the interval.
"I didn't have a rant," Harris said. "I just reminded them how good they are. I don't think we played with too much freedom in that first half, I thought it was very rigid and we didn't take care of the ball.
"We became far too predictable in our play but I was really impressed with the way Stevenage pressed us.
"Second half I thought we were really good and it was a good performance from Tom Elliott, two really good goals.
"If you're going to play with Tom in the team then you have to service him. It was two great balls from Fred Onyedinma and Shane Ferguson.
"Tom has the ability with his size, aggression and power to be able to score goals like that."
Harris made nine changes from Millwall's 1-0 loss at Nottingham Forest last week and admits his players were keen to impress after being given a chance.
"I thought there were strong performances, I thought a few people had a point to prove, not playing the other day," he said.
"Football is a beautiful game, if you don't play one game you think it's the end of the world.
"It's good to have some players in form, there's lot to think about for Saturday."
Stevenage boss Darren Sarll revealed he will only take positives from his side's display, despite missing crucial chances in the first half.
Sarll said: "First half I thought we played well and second half I thought we did okay. I know they had a chance at the end when we're trying to claw something back but I don't think that (goalkeeper) Joe (Fryer) had much to do in that second period.
"Sometimes when that ball goes up in the air and you're dealing with a player like Tom Elliott, it's very hard to deal with when you're moving backwards and you're trying to get the purchase off the ground.
"I thought we passed the ball well and looked good and as a manager I will take so many positives away from the game.
"The move which finished with Chris Whelpdale's attempt was a terrific move and it was synonymous with how we're trying to play. It was a lovely pass from Tom Pett and a good ball from Alex Samuel. Sometimes those are things that can decide games."