United matched their 4-0 season-opening win against West Ham by running riot in the closing stages at Swansea on Saturday.
Mourinho's United completed their victory with a devastating late burst in which Romelu Lukaku, Paul Pogba and substitute Anthony Martial scored between the 80th and 84th minutes after Eric Bailly had netted late in the first half with his first goal for the club.
Mourinho was delighted with his team's performance but insists they are not getting carried away by their strong start to the season.
"The word that better describes the team now [compared to last season] is confident", he said.
"In both matches, winning 1-0 at half-time, we didn't start the second half looking like we had to keep a clean sheet to win the match", said Mourinho.
Pogba admitted: "The first challenge was a yellow card but I was not anxious about the second one because it was not a foul".
"When you are 1-0 down you are always in the match", Clement told Sky Sports.More news: GST returns deadline put off to August 25
"The ref talked to me about it and I laughed at him because it would have been hard if we had a red card for that". Everything was very calm and under control. We have to improve. Goal-difference usually has a vital role to play in the relegation scrap towards the end of the season, and Clement knows that his side must avoid conceding more than three goals a game at all costs, just in case it comes down to another fight for survival in the league.
- Anthony Martial has been directly involved in three goals in his last two Premier League appearances (two goals, one assist), as many as in his previous 11 in the competition - both of his appearances this season have been from the bench.
Goals in the 80th, 82nd and 84th minutes added to a first half strike gave Manchester Uniteda thumping win over Swansea City on Saturday. New boy Lukaku was the man on the end of Martial and Mkhitaryan's build-up play, with the Belgian left with pleny of time to steady himself and finish strongly to double United's advantage.
Liverpool secured their first league win of the season, and inflicted Palace's second defeat, when Sadio Mane broke the Anfield deadlock after 73 minutes, although Christian Benteke should have given the visitors the lead moments earlier.
- This is just the second time a team has won their opening two top-flight games of a season by 4+ goals to nil (also Chelsea in 2010/11).
"We've still got a good squad here but absolutely we need more quality players to come in so that we've got a chance of being competitive this year".