Frank Lampard took his Everton side to north London looking to bounce back from defeat against Manchester United, but they came up short.
A Harry Kane penalty broke the deadlock just before the hour mark, while Pierre-Emile Hojbjerg sealed the deal with four minutes left.
Spurs largely dominated the contest at the Tottenham Hotspur Stadium, but Everton did enjoy good chances, which they could not take.
Summer arrival Onana believes Everton’s approach to the game worked and bemoaned their inability to take the opportunities which came their way.
The midfielder said post match on Sky Sports: “It [the game plan] worked. We stayed compact and did very well and stayed together.
“If we scored those chances, it maybe would have been another game.
“We can definitely build on that.”
Onana feels though that Everton must soon recover as they are due to take on Newcastle United on Wednesday.
“That penalty broke us down mentally but we haven’t got time to feel sorry for ourselves.
“We’ve got to bounce back at Newcastle.”
Everton saw four players booked in the game, with Vitaliy Mykolenko, Dwight McNeil, Idrissa Gueye and Neal Maupay going in the referee’s notebook.
