The 25-year-old winger scored five goals and created 51 chances in 44 Championship appearances for Leeds.
The former Brentford star has carried that good form into the European Championship in France and has been a key player for Northern Ireland so far.
Dallas did not start against Poland in their opening Euro 2016 Group C game, but his performance in the second 45 minutes was quite impressive.
The former Crusaders winger came on at the start of the second half in place of Paddy McNair and showed his quality.
The 25-year-old had a pass accuracy of 77%, created one chance, put in two crosses, and made one clearance and one block.
Dallas was rewarded for his performance in the 1-0 defeat to Poland with a starting place against Ukraine on Thursday evening.
The Leeds winger did not disappoint and was one of the best players on the pitch, as Michael O’Neill’s side won 2-0.
It was the former Brentford star’s low shot in injury time which forced Andriy Pyatov to push the ball into Niall McGinn's path for the second goal.
Over the course of the 90 minutes, Dallas took two shots, put in three crosses, attempted two dribbles, won 50% of his headers, and made two interceptions and one clearances.
A couple of areas whether the Leeds star could have done better were his pass accuracy and chances created.
Dallas did not create a single chance and had a pass accuracy of just 33% against Ukraine on Thursday evening.
However, the Leeds star’s performance was good enough to impress his former Brentford teammate and current Championship rival Alan Judge.