The Northern Irish midfielder scored twice from outside the box as the Whites secured a 2-1 victory at St. Andrew's.
The Northern Irish midfielder drilled home a low strike from outside the penalty area to open the scoring after 11 minutes, and latched onto Chris Wood's flick-on after half-time to control the ball on his chest and smash home a dipping volley from 25 yards to double his tally.
Though the 24-year-old has been a key player for the Whites so far in his debut season after signing from Brentford last summer, making 44 appearances in all competitions, those strikes were just his third and fourth goals for the club.
Dallas was delighted to get his name on the scoresheet once again but insisted his two sweet finishes were down to good fortune more than anything else.
He told the club's website: "It was a good phase of play for the first goal, I think it was six or seven passes and I just popped up in the hole. It happened to me in a similar position at Burnley and I put it into Row Z in the second half, so fortunately tonight it was able to go in.
"For the second goal, Woody won the header – I don’t think he lost a header all night. He won everything. You’ve got to take your chances to go in behind and, fortunately, I was able to control it and hit it. Fortunately it went in for me.
"As soon as you hit it you know if you’ve caught it well. It happened to me earlier in the season at Wolves from a similar one and it clipped the outside of the post. That was close, but sometimes they go in, sometimes they don’t."
Despite Clayton Donaldson's consolation and Alex Mowatt's contentious late red card, Dallas' brace secured a first victory in five matches for Leeds since mid-March as they look to gear up for a strong finish to the season.
The win lifted them over the 50-point mark for the season, and left them just two points away from breaking into the top half, which would be a small boost after another underwhelming campaign.