Leicester boss Claude Puel admitted Wes Morgan’s dismissal changed the game as the Foxes slumped to defeat against Everton.
The skipper was sent off midway through the second half with the score locked at 1-1 before Gylfi Sigurdsson’s stunner secured a 2-1 win for the Toffees on Saturday.
Morgan walked after collecting two yellow cards for fouls on Richarlison – who struck a seventh-minute opener – to be sent off for the second time this season.
And Puel believes Morgan’s 64th-minute red card was a pivotal moment.
He said: “The beginning of the second half we had good intensity, we had good chances and we had chances to score to make the difference and after the sending off, it changes the game.
“We’re disappointed of course, we didn’t start the game with enough tempo, it’s another time we conceded a goal.
“It’s too difficult after and we are giving ourselves a mountain to climb, we have to correct this.
“It’s a game with good balance, both teams can win the game and the sending off changed the game and gave them the opportunity to win.”
Ricardo Pereira’s first Leicester goal hauled the hosts level before the break but Sigurdsson’s 50th Premier League goal, when he found the top corner from almost 30 yards, won it for Everton with 13 minutes left.
Toffees boss Marco Silva said: “It was fantastic for Gylfi. His quality in that moment showed how good he is and the way he took the ball and shot was fantastic.
“I cannot talk to you about last season because I wasn’t here and it’s not fair but I know his quality.
“He’s playing a different role (to last season) and our style is completely different.
“He has worked to get ready for this, working in training with great intensity. It’s not just what he gives us with the ball but also what he is giving us without the ball.”