Wesley came on as a 73rd-minute substitute for two-goal Jonathan Kodjia and completed the scoring in Villa's 5-0 Carabao Cup quarter-final rout of the youngest Liverpool team in history.
It was only the 23-year-old's fifth goal of the season since his £22million club record move from Club Brugge in July, ending a nine-match drought.
The relief in scoring again showed on Wesley's face and Smith was pleased to see the Brazilian back on the score sheet.
"The idea was to get Wes on and he scored a really good goal, which was pleasing because I know he has been getting....at most of my press conferences I end up talking about him," said Smith.
"He is a 23-year-old player, in a foreign country, in the Premier League, which is one of the toughest leagues in the world, and he has scored four goals so far in his 17 league games.
"I think some of the criticism can be a little bit too harsh at times, but you could see the reaction of the players when he scored that goal, at how pleased they were for him."
Wesley was not the only player who benefited from the workout as Kodjia's brace capped his first start this season, while defender James Chester was playing his first game of the campaign after injury and fitness issues.
Despite the calibre of the opposition, who provided Villa with a stern test before being on the wrong end of a scoreline that flattered the home side, Smith drew satisfaction from the result and performance.
"This result will boost everybody's confidence," said Smith, whose side sit just above the bottom three in the Premier League following a wretched run of six defeats in eight games.
"This football club has a proud history in this competition, we've won it five times before. It's great for the club to be back in the semi-finals, a two-legged affair, possibly against one of the biggest clubs in this country. It will be a great fillip for the club."
Although conceding to "a weird feel" about the game and admitting "it wasn't like it was a quarter-final", Smith added: "Yes, I would love to have been playing Liverpool's first team, but they had other things they had to go and do.
"For us, this is the first major competition of the season, and if you are not in Europe, or the Club World Cup, then you've only got three trophies to win.
"So I get as much satisfaction from this as I did when we beat Crewe 6-1, the Brighton under-23s, more or less, and Wolves under-23s in the other rounds."