Nelsen, in his second season as Toronto manager, was one win away from matching club's best ever high of 10 victories in a season - with 10 games to go in the MLS season.
After finishing ninth out of 10 teams in the MLS Eastern Conference last season, the side are currently fourth and still a chance to make the playoffs with nine wins, nine defeats and six draws.
But following Sunday's 3-0 loss to New England, Nelsen blasted the club's general manager Tim Bezbatchenko, putting the New Zealander's job on the line.
Bezbatchenko responded by firing Nelsen and his entire coaching staff, the Toronto Star reports.
"I think everyone would agree - the coaches, the players - that over the last 12 or so games, it hasn't been good enough, at least for making a run in MLS," Bezbatchenko said before Sunday's encounter against the New England Revolution.
However, Nelsen responded to Bezbatchenko's comments through the media after his side were handed a heavy loss.
"I've been in some pretty pressure situation games and this wasn't one but it was made into one," Nelsen said. "To be fair, we've got to be better than that.
"We're used to - as most Toronto teams are - hearing it from the outside, that's why it should never, ever come from inside. Ever.
"I'm not panicking, nobody's panicking. Whatever is being said from anyone at TFC from the coaches and the players, we're more than confident in what we have to do. We have 10 game, five at home, five away, it's in our hands."
According to reports, Bezbatchenko wasn't impressed with Nelsen's comments and fired the 36-year-old.
That leaves Nelsen with a 26 per cent win-loss record in the MLS over 57 matches.
- New Zealand Herald
