St Mirren "could have made it more comfortable" as they downed Dundee and strengthened their bid for a top-six finish in the Scottish Premiership.
Stephen Robinson's side are nine points clear in fifth place after beating their nearest league rivals thanks to goals from Mikael Mandron and Toyosi Olusanya.
The hosts had to play the final 10 minutes with 10 men after James Bolton needlessly flew into a challenge on the halfway line and saw red.
"Dundee owe Trevor Carson, he made a few stunning saves to keep the score down," Robinson told BBC Scotland.
"They're a tough nut to crack. They have a lot of experience, they know how to win, and we had to make sure we weren't going to be done by a set-piece or counter-attack.
"Nothing is done at this stage. We have a lot of tough games coming up. Nothing is easy at this level. We need to do the basics right, we've done that well recently."
Dundee remain sixth, ahead of Hibernian on goal difference.
Robinson had played up the importance of this game, and that pressure might not have been helped by the match being delayed by half an hour after Dundee were held up in traffic.
However, the hosts started the better and knocked the ball around nicely while being let down by a lack of composure.
The first sniff of a chance came to Mandron after he was played through by Kwon Hyeok-kyu, but Carson got down well to save. Alex Gogic and James Scott had headed opportunities, glancing them both wide.
Dundee's best chance of the game fell to Owen Beck. The left-back burst clean through, but chose to pull the ball back to his left foot and slipped before he could unleash a shot. The moment was effectively gone and he eventually dragged wide.
The second half struggled to kick into life but substitute Keanu Baccus sparked St Mirren's attack when his half-volley grazed the crossbar.
The opener followed soon after. Mandron collected a loose ball on the edge of the box, chested it down and shot. It wasn't the cleanest strike, but it squirmed awkwardly under Carson and into the top corner.
Things looked less assured for the hosts when Bolton was sent off. Having been booked earlier in the second half for scything down Beck, diving into Owen Dodgson on the halfway line was reckless. Steven McLean was asked to review his decision, but stuck with a straight red.
The momentum swung to the visitors and they had a strong handball shout turned down, after which manager Tony Docherty was booked for his protestations.
And then, the gut punch. Dundee were caught with men forward and Olusanya burst free - onside despite Dodgson's best efforts - to tuck away the chance and ensure all three points.
Player of the match - Kwon Hyeok-kyu (St Mirren)
St Mirren rise to occasion to punish rare Carson mistake - analysis
You don't see Carson make too many mistakes. What will be all the more sickening for the Dundee goalkeeper is that it came against his former employers.
St Mirren looked like the side higher in the league. Some of their passing play was superb, but too often they lacked a cutting edge in the box.
They were handed a gift by Carson, and snatched it with both hands. Now the Paisley side are firmly in the driving seat for the top six.
Dundee will be happy to get back home after a brutal run of eight away fixtures in 10 games.
The reality is they are nine points from fifth place, and seven from 11th. They cannot afford to be complacent.
What the manager said
St Mirren manager Stephen Robinson: "It's our third win in four games and fifth in 10. There's a real belief in the squad."
Dundee boss Tony Docherty: "It doesn't sit well with me. It was a difficult game, the pitch was poor and really difficult to play on. We tried to pass it, but it was a long-ball, second-ball game. That's their style of play.
"We've got a handball in the 87th minute from a shot that is going in, or hitting the post at least. We don't get that decision, they don't go over to VAR. I'm perplexed, I'm asking questions, because I'm trying to protect our football club."
St Mirren welcome Celtic in the Scottish Cup last 16 on Sunday, while Dundee host St Johnstone in the league on the same day (both 14:00 GMT).