The former New Zealand international is looking to remake a franchise that has traditionally been the MLS doormat. Nelsen, who inherited a side that went 5-21-8 last year, has a long way to go but was clearly chuffed by the performance of what was essentially a young B team.
"I know now that I've got 22 players that can put on the Toronto shirt at any level," he said.
Take out 33-year-old Danny Califf, 27-year-old Stefan Frei and 26-year-old Justin Braun and the rest of Nelsen's starting 11 was aged 20, 20, 21, 21, 22, 22, 23 and 24.
"To play with the maturity that they did was really impressive," Nelsen said of his youth. "The scary thing, the good thing is that this squad will get better. We will bring in players who are going to get better and better and better. And we will improve it.
"This is just the foundation, the basics that we have to adhere to. We're always looking to improve every facet of every part of our organization"
Argentine midifelder Matias Laba is expected to be the next in the door.
Add the showing by the young guns to a first team that has gone 1-2-4 in the league — and could have four wins had it not been for some late lapses — and Nelsen is entitled to feel good about the "baby steps" TFC is taking.
Montreal manager Marco Schallibaum, meanwhile, had no qualms with Wednesday's result.
"Toronto merited the win," he said, pointing to mistakes in the second half.
Facing a crowded league fixture list (both have six games in 18 days), the two coaches reached deep into their squad for a starting 11. And it showed, with some dreary stretches of play before a small crowd of 11,043 on a chilly evening at BMO Field.
Toronto made nine changes to the team that gave up a stoppage-time goal in a 1-1 tie with the visiting Houston Dynamo in league play Saturday. And Montreal made six changes to the starting 11 from its last game, a 1-1 tie with Columbus on April 14.
The revamped lineup paid off for the home side as Doneil Henry and Andrew Wiedeman scored second-half goals to give Toronto the win. The two teams meet next Wednesday in Montreal with the Impact needing to find some offence.
Montreal president Joey Saputo took to Twitter after the game.
"Responding to the comments from our fans...no one is more disappointed than I am, We gambled and lost; time to regroup. It ain't over folks," he said.
Schallibaum defended his selection.
"Alessando Nesta and Marco di Vaio can't play today and also be fresh for Saturday," he said.
And he said those who played had looked ready in the buildup to the game, although he admitted their performance on the night was "another reality."
Montreal (4-1-1 in league play) defeated Toronto 2-1 when they met March 16 in MLS play at the Olympic Stadium.
Both teams were vastly different Wednesday.
Evan Bush filled in for starter Troy Perkins in the Montreal goal.
Jeb Brovsky, Karl Ouimette, Hassoun Camara, Patrice Bernier and Justin Mapp were the only starters who figured in the Impact's starting 11 in its last league outing.
Toronto rang in even more changes.
Frei, serving as captain in the absence of defender Darren O'Dea, made his first start in the Toronto goal since breaking his nose in the pre-season opener. Frei, who subsequently lost his starting job to Joe Bendik, had an uneventful night.
Only Ryan Richter and Braun made it into the cup squad from Saturday's starting 11 against Houston.
There were eight Canadian starters on show Wednesday, five for Toronto and three for Montreal.
The Vancouver Whitecaps rallied to defeat FC Edmonton of the North American Soccer League 3-2 at Commonwealth Stadium in the other semifinal.
The second legs are scheduled for May 1 in Montreal and Vancouver. The final is set for May 15 and 29.
The tournament winner represents Canada in the CONCACAF Champions League. Montreal won the inaugural competition in 2008 with Toronto taking the next four.
Montreal has never beaten Toronto in Canadian Championship play, holding an 0-7-2 record against its Ontario rival.
After a stagnant first half from both teams, Toronto came out with a new sense of purpose. And the home side struck early in the second half.
Henry, who turned 20 on Saturday, opened the scoring in the 49th minute, adding a much needed shot of excitement to a drab evening. It was his second career goal in Toronto colours.
The goal came after Wiedeman kept a ball in play from a corner. He raked the ball back and Jonathan Osorio put the ball back into the penalty box. The ball bounced back off a Montreal defender to Henry just outside the penalty box, directly in front of goal, and the tall defender hammered home a right-footed shot.
It was a beautiful strike in an ugly game of soccer.
Nelsen liked the rest of Henry's performance as well.
"The icing on the cake is the goal obviously, but for me I like to see what he did in the rest of the 93 minutes beside that 10 little seconds of brilliance. The other 93 minutes he was very solid and he defended very well."
Montreal introduced forward Daniele Paponi, its new Italian signing making his MLS debut, and Argentina's Andres Romero in the 60th minute in a bid to inject some offence.
But Toronto continued to do the attacking on what was a disappointing night for the visitors.
Wiedeman, released by a fine pass from substitute Luis Silva, made it 2-0 in the 81st minute on a clinical shot from just inside the penalty box. He had a good chance at a second goal in stoppage time but shot at the goalkeeper.
If the aggregate score is tied after Wednesday' game, the team with the most away goals advances. If that does not settle the mater, there will be a 30-minute extra time period and, if needed, a penalty shootout.