Club-record signing Wilfried Bony scored a brace as the Swans ran out comfortable winners in the Europa League qualifier.
He told Sky Sports News: "It's great to play these two serious games before the league starts. It's great for us to play a very important competition rather than two friendlies. I was happy to start now because of this.
"We can use these games as preparation for the Premier League. We know cup competitions are important but the Premier League is our daily bread. It is where we want to be and it is where we want to consolidate ourselves as a squad and a club this season.
"The players know what we want to do, but for now we just have to think about the one game we have played. We have conceded only one goal in pre-season, that gives confidence to the team and we have looked strong at set-pieces. That was one of our weak points last season and it looks like we are improving there."
The Swans host United in David Moyes's first league game as United boss at the Liberty Stadium on August 17.