The Blues enjoyed the best of an entertaining game in which both sides showed intent to get their scoring boots on.
“I’m really happy,” he said.
“First of all with the result and then with the way we played, I thought we played some really good football in the first 45 minutes.
“After the 4-2 we played it really clever and controlled the game.
“A really good team performance today.
“It’s always difficult against Leicester. I think Morgan did a great job in front of the centre backs and a lot of times in the first half we had an extra player in midfield.
“The whole team played really well on a high level.”
When asked about the two stand-out players of the day, Ross Barkley and Romelu Lukaku and their contract situations, Koeman was less confident.
“We try but the final decision is always with the player,” he admitted.
“The situation with Ross is different as he only has one year left on his contract but Rom has two years.”