The performance capped off a memorable week for the United schemer, who made his Scotland debut in midweek after coming off the bench against Northern Ireland.
The Leeds boss said: "It has been a huge week for Robert, with his first game for Scotland and now this excellent performance.
"He is a lad who deserves everything that comes his way because he works so hard at his game.
"In the 92nd minute he was still closing down Bristol City's full-back and playing his part for the team.
"Max Gradel is a similar type of player on our other wing and he also took his goal well and played a major role in our victory."
Source: PA