Grealish scored the visitors’ first goal inside the opening four minutes as the Villans ran riot in West London. Conor Hourihane and Tyrone Mings were also on target.
Smith revealed during his post-match conference that Grealish’s goal was worked out in training.
“We've been working on breakthrough runs with Jack and it was a great run, great finish and it's all you can ask for. We felt they would be quite high [defensively] and there would be space to run into them,” the former Brentford coach said.
"[Grealish] is a special player and a special talent. I think he would be the first to say we've improved as a team. We've improved and it helps take the pressure off him a bit, it was an all round great performance."
Grealish has established himself as one of the best players in Aston Villa since making his debut for his boyhood in May 2014.
The 25-year-old was arguably Villa’s best player last season after he scored eight goals and provided six assists which helped Smith’s men to avoid relegation.
He was linked with a move away from the Villa Park but the former Notts County loanee decided to commit his long-term future to Aston Villa by signing a five-year contract.
