The imposing Senegal midfielder wasted little time in throwing his weight around, showing all the dynamism, determination and skill that endeared him to fans of former club RSC Anderlecht.
But Kouyate told West Ham TV: "I think I can still do better.
"I'm not yet at 100 per cent, so I'll be doing even more work. Now that the league's begun, I've got to work hard in training to find my rhythm.
"As soon as I'm at 100 per cent I'll really be able to give more than I was able to on Saturday. Not bad, I know, but I'm certain that I can do better still."
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