The Portuguese, signed from Sporting Lisbon in January, has scored three goals and provided three assists in eight appearances for the club.
One of those assists came in Sunday's 2-0 derby win over Manchester City, and Shaw was impressed by his performance.
"At times we know he's going to lose possession, but we need them sort of risk passes that are going to unlock defences," Shaw said.
"He's been a brilliant signing so far and he's already come in with a few assists and a few important goals.
"We will keep pushing the standards and we'll keep pushing him because there's so much more from him to come."