Rangers got the better of their Old Firm rivals Celtic in the semi-finals of the Scottish Cup at Hampden Park in Glasgow.
The Gers won the game 5-4 on penalties after it finished 2-2 in extra time, with the Glasgow giants booking a place in the final of the prestigious cup competition.
Dallas, who played under current Rangers manager Mark Warburton at Brentford, was impressed with the performance of the Gers.
The Northern Ireland international, who can play as a winger or an attacking midfielder, has praised Rangers defender Rob Kiernan for his performance against Celtic on Sunday afternoon.
A massive statement from Rangers.When they played Celtic couldn't get near them. @KiernanRobbie outstanding until he went off— stuart dallas (@dallas_stuart) April 17, 2016
Dallas has scored one goal and created 41 chances in 39 Championship appearances for Leeds so far this season.
The attacker has a pass accuracy of 74% and a shot accuracy of 38%, and has won 20 headers, 27 dribbles and 31 tackles.