Kieron Freeman sent Sheffield United top of League One with a late winner to beat Northampton Town at Bramall Lane.
It looked to be a stalemate between the Blades and Chris Wilder's former team, but the United wing-back popped up in the 88th minute to smash home the winner.
It took United to 50 points, and top spot in League One - with Scunthorpe United kicking off later in the day - to send the majority of the 24,194 crowd home in good spirits.
Blades boss Chris Wilder said: "I'm full of admiration for our players for making it our day. We ended up finding a way to win the game.
"We faced stubborn opposition so it was a great result. They sat deep and I totally understand that and respect that. Credit to them for frustrating us.
"Maybe we lacked a bit of quality and it just didn't seem to be happening, but we kept our patience.
"At the end we went for it and I want us to go for it. It's a good way to sign the year off.
"The race is on now and we're bang in the middle of it. I want us to kick on and we've got the desire to do that.
"We've got a lot of good things going on at the club. We'll keep improving and we have to overcome anything that's put in our way."
United made one change from the side which beat Oldham Athletic on Boxing Day, striker Clarke coming in for Matt Done, who dropped to the bench.
The Cobblers had plenty of Yorkshire links in their side, including former Rotherham United forwards Alex Revell and Sam Hoskins, and Barnsley defender Lewin Nyatanga.
It was a frenetic opening, with both sides attacking at will. Paul Coutts saw his long-range effort well saved by Adam Smith, before side-footing wide after good work from Sharp.
Northampton's Revell was troubling United's defence, while Paul Anderson saw his header fizz the wrong side of Simon Moore's post.
Mark Duffy saw his free-kick deflected wide, as United started to assert themselves on the game.
Northampton fans chanted "there's only one Chris Wilder" to their former boss, and the 1,650 visiting fans were out in force at the Lane.
Ethan Ebanks-Landell was booked for blocking Matt Taylor's surging run, but the resulting Cobblers' free-kick drifted wide.
Clarke came close to breaking the stalemate in the 37th minute, but just missed out on Freeman's low, hard cross.
United seemed sluggish after the break, and struggled to break down a well-organised visiting defence.
Wilder brought on Caolan Lavery for Clarke, with 30 minutes remaining, as he looked to find a breakthrough.
That seemed to perk United up, as they enjoyed a sustained spell of pressure in front of the Kop, with Northampton lucky to escape a couple of goalmouth scrambles.
Stefan Scougall and Matt Done were added to the attack, replacing Chris Basham and Daniel Lafferty, as Wilder pushed for the opening goal.
But it was at the other end where a goal nearly came.
It needed a superb save from Moore to deny Taylor, after his long-range free-kick looked destined for the back of the net.
Duffy drilled a low shot wide, for United, but the hosts finally netted the goal their play deserved.
And it came from an unlikely source, in wing-back Freeman, who blasted home from close range in the 88th minute.
And the Blades could have quickly added a second, but Scougall fired over the crossbar.
'We are top of the league' chanted the Blades fans, as they could finally celebrate after a tense lunchtime match.