The former Walsall man has been a regular target for fan criticism this season but he was able to silence a few of those detractors with a well taken goal against the promotion chasing side.
The Saint Kitts and Nevis international also dazzled United with his range of passing, notably a fine reverse pass to Lasse Vibe that almost resulted in a goal.
"If Rom keeps performing like that his detractors will get fewer and fewer. His first 70 minutes on Saturday were good but he was excellent for the 90 tonight," he said.
Smith also hailed centre-backs Harlee Dean and Yoann Barbet after they kept Leeds striker Chris Wood quiet all night, saying: "They were both fantastic and hardly gave him a sniff.
"Harlee was excellent in the air and he is getting better and better as a Championship player and as a captain."
The goal was Sawyers' third strike of the campaign, after the ones against QPR and Eastleigh.