Manchester United boss Erik ten Hag was delighted with victory at Southampton.
United won 1-0 thanks to Bruno Fernandes' second-half effort as Cristiano Ronaldo again started the game from the bench.
Ten Hag said: "I think the players learnt some lessons from Brentford. We were more compact on the long balls. Of course we were really happy. The goal we created, we could have made more. You hope to have more control in the last 30 minutes of the game.
"Before half time we already had the best chance of the game. I was satisfied. At the start of the game we could have created more. It is the start of the season, it is tough. You have to battle and we did that today so we were rewarded.
"It was a fantastic finish. I am really happy for Bruno [Fernandes]. But I think it was the best part of us. We kept control straight after half time. We moved it around and we created three really good chances straight after half time and that is how I want us to play.
"I still feel there is room for improvement, to control more, but we are not that long in our way. We can improve that is clear."
He also said: "It has to be the standard for Manchester United. It has to be normal but also you celebrate every win because you have to fight for it. We learnt from our lesson in Brentford.
"There is room for improvement but there was also some really good football. The last half an hour was a survival and there I think we can do better.
"There was not always pressure on the ball but [the defenders] stayed compact and were straight in the duals. I was comfortable they would deal with it. The finish [from Bruno Fernandes] was magnificent but the part before, it was a team goal. We built it up from the back and there were some more moments straight after half time where it was well played from the team. We have to improve in possession.
"The win against Liverpool gave us a lot of belief because we knew we could compete against one of the best teams in the world. Still at the start of the season it is really tough and hard work so everyone in the squad needs to be conscious of that.
"The transfer window... you don't know what to expect. We will see. As Manchester United you always have to try do better so we can see if we can strengthen the squad, if not we will do with what we have got."