Dealing with Millwall's physicality was the key to success according to Bristol City boss Dean Holden who was left satisfied with a job well done following his side's comfortable 3-0 victory at the Den.

The win sends the Robins into the fifth round of the FA Cup for just the second time in 20 years, where they will face Premier League opposition in the form of Sheffield United.

A Famara Diedhiou penalty just after the half-hour mark, when the Senegalese international was hauled down by Millwall goalkeeper Frankie Fielding following a neat Zak Vyner through-ball, gave City the lead slightly against the run of play but they dominated proceedings after the break.

Nahki Wells' deflected free-kick made it 2-0 and the Bermudan forward then slipped in Antoine Semenyo, who finished calmly to put the game beyond doubt 18 minutes from time.

Holden could not find fault with his troops as they now gear up to try and shock top-tier opposition, which they narrowly failed to do in their previous fifth round appearance in 2019 – a 1-0 defeat to Wolves.

"Coming to Millwall is always a tough fixture but we handled the physical pressure really well and it's a good afternoon's work," said Holden.

"We were aggressive in our defensive work but there was also a huge improvement in what we did with the ball.

"There were two key passages of play that showed our quality. The first was in the lead up to the penalty when we carved them open and then at the start of the second half when we just stepped on it.

"Once we raised our level, they couldn't get at us and Nahki deserved that bit of luck with the free-kick because he hit a superb one in the first half which Frankie (Fielding) did really well to keep out.

"The third goal just rounds it off. It's brilliant vision from Nahki to play that ball and some finish from Antoine with his left foot.

"To win here by three goals, keep a clean sheet and get into the next round of the cup is hugely satisfying."

With one eye on a hectic schedule of league action, Millwall boss Gary Rowett made eight changes to the starting XI that started against Huddersfield in midweek.

They had their moments, especially in the first half when Mason Bennett, Tom Bradshaw and Ryan Leonard all went close, but Rowett accepted his team selection gamble did not pay dividends.

"I'm disappointed, of course, but we had to look at this game in isolation having come off the back of four away games," explained Rowett.

"We took a bit of a gamble that hasn't come off. We had to make changes. The reality is that the FA Cup without fans isn't great for us and this isn't about excuses.

"We still put out what was an attacking side and a team that I thought could win us the game, but we couldn't capitalise on a decent start.

"We should have done better if truth be told. We know there is an issue with creativity in the final third but then when they score their second, that kills it. It's frustrating because we should never have given that free-kick away.

"We had to reflect on where the FA Cup is in terms of priority and we took a bit of gamble but some players haven't taken their opportunity."