Chester was pleased – and relieved – to be through to the quarter-finals, but admitted the performance was below-par.
Wildcats led 22-0 after 16 minutes, but were only six in front with seven minutes remaining before Tom Johnstone crossed twice to seal it.
Chester’s men will travel to Huddersfield Giants in the quarter-finals next month.
Toulouse, from Kingstone Press League One, outscored Wakefield 22-18 in the final hour and Chester said he was “nervous” before the game and at half-time, when Wildcats led 22-10.
He admitted to using some “choice words” to his players and added: “I thought they out-enthused us in the last 10-15 minutes of the first half.
“But if you had said to me before the game you’re going to be in the next round, I’d have taken it.
“I am delighted we are in the quarter-finals.”
Chester, who was in charge of Hull KR when they reached the final last year, felt their good start worked against Wakefield.
He said: “Toulouse had a real dig, they are a good footballing side. I think that first 15 minutes was probably the worst thing that could have happened to us.
“We seemed to score with ease, but in the second half our completion rate was 43 per cent and we did a lot of defending. Fair play to Toulouse, they threw the ball around well and caused us a lot of problems.
“I was disappointed with our attitude, our line speed and our defence, especially our short-side defence. We need to be better. If that had been a Super League side, I think they might have turned us over.”
Johnstone scored four tries in total, but Chester insisted: “I thought Anthony England was our best player. He carried the team and was the only one who got us going forward.”
The full-quarter-final draw, to be played over the weekend of June 23-26, is: Hull v Catalans Dragons, Wigan Warriors v Castleford Tigers, Warrington Wolves v Widnes Vikings, Huddersfield Giants v Wakefield.