Dallas has also earned rave reviews this season and the highly versatile Northern Ireland international's stock rose even higher last weekend when he put the brakes on Manchester City's title charge with both goals in a shock 2-1 win at the Etihad Stadium.
"The place that Dallas occupies in the team at the moment is the role that (Mateusz) Klich usually had," Bielsa said, referring to Klich's recent loss of form.
"In the majority of the games that the team played, he (Klich) was one of the best players in our team.
"When Dallas started to play in this position he started to show different ways of playing in it.
"To score goals was a clear expectation when he started to play in this position and as the minutes go by he manages to have a marked influence or definition in the finalisation of our chances."