Saiz was at his dangerous best in Leeds’ first game of the season, which they won 3-1 against Stoke City.
The Spaniard looks likely to thrive in Bielsa’s system, which encourages his most creative players to get on the ball as often as possible.
And the Argentine boss said: “He is a creative player, he has the capacity to find solutions by himself. This makes him a special player. We saw this on Sunday.”
Saiz was brought to Leeds by Thomas Christiansen last summer, and his performances over the first half of the campaign were outstanding.
The playmaker looked like one of the brightest attacking weapons in the Championship when he first arrived, but his form dipped after January.
Saiz will be looking to be more consistent this term, as Leeds once again go for promotion.
The Whites have started their campaign in brilliant form, after dispatching with title favourites Stoke with relative ease.
Leeds are next in action at the weekend, when they take on Derby County at Pride Park.