But substitute Colwill produced a rare moment of class to seal the points in stoppage time as he danced between two defenders down the left flank before smashing a shot high into the net.

Harry Cornick had Bristol City's clearest sight of goal but was denied by Jak Alnwick.

Erol Bulut's Cardiff have won five of their seven home Championship fixtures this season, meaning they are already just one short of their final tally of league triumphs on this ground in 2022-23.

That sharp upturn in home form - the Bluebirds extended their unbeaten run on their patch to six games - is key to a growing feeling of optimism at Cardiff about their prospects for this campaign.

Bristol City, meanwhile, are left searching for improvement having succumbed to a fifth defeat in their last seven games.

Nigel Pearson's team drop to 15th in the table, while Cardiff climb to fifth.

This was a meeting of a Cardiff side with one of the better attacks in the second tier and a Bristol City team who boast one of the division's meanest defences.

Yet it was the Robins who threatened first, as Dimitrios Goutas lost possession deep in home territory and Cornick's shot flashed wide of the target thanks to a slight touch from Cardiff goalkeeper Alnwick.

It was a first half of few opportunities at either end, but from that point on Cardiff looked the more likely scorers.

Callum Robinson was denied a chance to shoot at goal when he was chopped down just outside the box by Rob Dickie, before Karlan Grant's far-post volley was gathered by goalkeeper Max O'Leary.

Cardiff, on their best home run since an eight-game unbeaten streak in the 2019-20 campaign, broke the deadlock in fairly simple fashion when Joe Ralls' right-wing corner was headed in from point-blank range by Ng.

Perry Ng rises high to head Cardiff into the lead

The former Crewe player has scored only 12 goals in a senior career spanning eight years, with three of those coming in the last month.

Bristol City's cause is not being helped by a lengthy injury list, yet Pearson's team came back into the contest in the second half.

Jason Knight's 25-yard drive drew a sharp save from Alnwick, then Andreas Weimann hooked one effort off target before heading over the bar.

Bristol City substitute Ephraim Yeboah saw penalty appeals turned down before Wales international Colwill, who has struggled for game-time this season, gave a reminder of his undoubted quality with his first league goal in 19 months.

Cardiff City manager Erol Bulut:

"It was not an easy game. After the last game where we won 4-0 against Huddersfield, I said to my team we cannot celebrate, we have to continue to work.

"Today again, hard and good work and a good result for my team. I am glad to see this performance from the players today.

"If you see the second half, the opponent was pushing a lot, trying to create. We needed that goal to be more relaxed and Colwill did it great."

Bulut on Nigel Pearson's comments about Cardiff:

"This is his opinion. Football we play on the field. Whoever gives a better performance, scores and doesn't concede goals is going to win the game, and right now we are doing this really well.

"Of course we cannot say we have the best team in the league but our players are giving everything, every game to be in this position. We will continue to work like that."

Bristol City manager Nigel Pearson:

"There wasn't much in the game. We conceded two goals from our own possession but we didn't create much. Cardiff might be doing okay but I wouldn't put them up with the best sides at all.

"In our recent games against Leeds, Ipswich are going well, Leicester - they're all games we lost by the odd goal.

"It's a competitive league and if you don't make good decisions on the pitch, sides will turn you over. It's more difficult when you've got a young and inexperienced bench.

"They (Cardiff) have not really created anything in the game. Most of their stuff has come from us turning the ball over.

"No-one here will look at that game and think Cardiff are a really good side compared to Bristol City. I don't think it was a game of a lot of a quality. It was a game with a team in a good seam that capitalised on our mistakes. They didn't outplay us."