The former Benfica star impressed in their friendly win over Olympiakos.
"I thought he was brilliant," said Henderson to liverpoolfc.com. "It's his first game and he gelled really well. He kept getting the ball, taking players on; he looked really lively so I think he'll be delighted with his game.
"He's very creative; he's great with the ball, playing one-twos and [making] runs in behind all the time so he's a great threat for us going forward, especially on the counter-attack.
"He's a great signing and a great plus for us."
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