Both men were on the scoresheet in yesterday's victory over Newcastle United.
"It is great to have him here. Luis is doing very well so far, and I am very happy to play alongside him," said Kuyt.
"It is great to have a player like him in the team. He is always moving, always trying to create something, and the moment he gives you the ball he is already on the move again to get it back.
"It makes it so much easier for you.
"Everyone could see we had problems earlier in the season but then things changed and everyone can see that when you add two quality players to a team, then things can change."