The 57-year-old believes conceding three goals was an unfair reflection of his side's display, before admitting his anger at Mike Dean's decision to book Bryan Ruiz for diving
The Blues needed a David Luiz rocket to break the deadlock at Craven Cottage, before two John Terry headers have the result a far more comfortable look.
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"You saw the goalscorers," he told Sky Sports. "John Terry two and David Luiz one, so the defenders scored and that was the story of the night.
"I thought we were great in the first half. We should have scored in the second minute but didn't and then we didn't close Luiz in midfield. It was a great shot but we could have closed it down.
"For the second goal we couldn't clear the ball so we didn't push out to the edge of the box. When that goes in it is always difficult, especially against a good team. The third goal is a corner as well.
"You see the score, it is a bit harsh. They deserved the goals but I thought we were maybe the better team for the first half an hour. That's the frustrating thing - we couldn't capitalise on it."
The Dutchman was also left outraged by referee Mike Dean's decision to book attacker Bryan Ruiz for simulation, insisting his player did not dive when inside the penalty area.
"I think it was a ridiculous situation," he added. "Of course, you could argue maybe that the other player didn't touch him.
"But you could see he lost his balance because of the defender. I can live with a goal kick or whatever but a yellow card? It was never a dive. Anyone could see that. He is the only person on the pitch who thought that was a dive."