A strike from Pape Sarr and Lisandro Martinez's own-goal late on gave Spurs a 2-0 victory at the Tottenham Hotspur Stadium on Saturday.
Onana, who kept his first clean sheet for the club in Monday’s 1-0 win over Wolves, felt Tottenham weren’t superior to United but was frustrated that the Reds couldn’t capitalise on the goalscoring opportunities they created - particularly in the first half.
“I don't think that they were better than us,” the goalkeeper told Sky Sports after the match. “We made some mistakes second half, but football is not always about one half.
“I think we started the game really well, we created chances.