Burton Albion manager Nigel Clough knows Sheffield United well - and he believes they could take some stopping.
The Brewers boss was in the hotseat at Bramall Lane during the 2013/14 and 2014/15 seasons in League One, taking the Blades to the third-tier play-offs in that second campaign and memorably guiding them to semi-finals in the FA Cup and League Cup during his tenure.
When he was sacked in May 2015, Nigel Adkins was the man to follow him - but it is under Chris Wilder that United have risen to the Championship, and are now among the division's pacesetters.
The Blades would move top of the table if they defeated Albion at the Pirelli Stadium on Friday night, with Clough wary of two valuable assets that are pushing the Bramall Lane side on at the moment.
And he knows very well how the Sheffield United juggernaut can be a tough one to slow down once it is moving in the right direction.
"It was a very enjoyable couple of seasons, to go from third-from-bottom to seventh, and then the play-offs and a couple of semi-finals along the way," said Clough when reflecting on his time as Blades boss.
"It's one of those clubs that, once you get it turned around, it takes some stopping.
"The two words we've used talking about them are 'momentum' and 'confidence' - and I think they have those two things in abundance at the moment.
"The team, the club and the manager, all those components are there.
"And what we know from our experience there is, when they do get that crowd behind them, there are very few places like it.
"Home and away, their support is absolutely brilliant, and it's been a key factor in turning things around."
This game will be the first meeting between Burton and the Blades in the second tier of English football, with the sides last facing off in League One in 2015/16.
And this weekend's clash is just the latest reminder of the quick progress Albion have made in reaching this level.
Clough has previously pitted his Brewers against a Wilder-led team, when they were facing Halifax Town and Oxford United in the Conference.
And the Brewers boss believes those experiences are still proving valuable, a decade or more down the line.
"It (Sheffield United) is certainly Chris' club - he played for them, there's the story that he was ballboy for them as a kid," added Clough.
"So for him to go back there, it's always been one of those things that has been inevitable at some point.
"It's lovely to see him back there and doing so well.
"We go back a long way, because we used to play against Halifax in the days here when Halifax were struggling financially and we used to play them in the Conference.
"We used to have some good old battles.
"So whenever we see him, we say, 'do you remember those days when we were battling it out?'
"It's always nice to have a chat about those.
"And that experience, for us both, has been absolutely vital."