Rotherham United were left sickened after a stoppage-time Colchester equaliser meant they had to settle for a 2-2 draw at the New York Stadium.
Denis, who started out with the Millers before a long spell with the Blades, came back to Rotherham in 1999 and has missed only a couple of games since.
Denis, who was born in Attercliffe, is 65 and is to retire at the end of the season.
There was a cracking start to the game with both sides scoring in the opening eight minutes.
After Agard fizzed a 25 yarder over the top, Colchester’s first threat brought a corner from which they scored in the sixth minute.
Garbutt took it from the right, BEAN - who had a loan spell with the Millers a few years ago - got in front of Mills at the near post and his stooping header bounced in off the far post.
Rotherham made the best possible reply two minutes later, with TUBBS netting his first goal for the club.
Skarz delivered from the left into the heart of the area, it just cleared Bolger and Tubbs controlled the dropping ball with his right foot and then finished off with his left from six yards.
Tubbs might have had another shortly afterwards.
Bradley lifted the ball forward, he was in space but the ball was dropping awkwardly and it just got away from him as he tried to take control.
The equaliser had given Rotherham some momentum and they forced the visitors back. Then on 21 minutes, they were in front.
It began with Arnason’s long throw. A loose ball came to Frecklington, he headed into the danger area, followed up to make a challenge and the ball popped loose for AGARD to knock home from close range.
Frecklington and Agard both had shots desperately blocked as Rotherham’s pressure mounted. The home crowd were hoping that Revell might get on the scoresheet next, and he might have done when he got in front of his marker from O’Connor’s free-kick but couldn’t make sufficient contact.
A third goal looked on the cards at any time and Bradley almost got it, and then Revell and Tubbs combined superbly. Tubbs ran on, crossed the ball in low aimed for the big striker only for Wilson to make a vital covering clearance six yards out as Revell stretched.
Bradley looked to have won the ball only for the referee to blow up and he then booked the right back, much to the crowd’s disgust. Veteran striker Morrison, once with the Owls, had words with Steve Evans who, arms outstretched, was complaining about the decision.
Rotherham might well have added to their lead.
O’Connor’s cross found Revell at the far post. He nodded across the area, it was falling nicely for Agard but Tubbs went for an overhead kick and fired over the bar.
After the early blow, it had been a tremendous response from the Millers who had dominated the half.
Rotherham might have had a goal inside 20 seconds.
Agard took on Garbutt, got into the area, crossed low and Tubbs got in at the near post but the contact wasn’t sufficient to beat Walker.
Poor marking by the Millers let in Eastmond and Rotherham were grateful his 18 yarder got a deflection wide.
An important interception stopped a Skarz centre reaching Tubbs in front of goal. Then Rotherham had a let-off.
They gave the ball away in the U’s half and were caught out as the visitors broke and it was left back Garbutt who moved into the area only to roll his effort wide of the post.
Colchester, as they had to, were doing more going forward this half but Rotherham had the next threat.
Agard burst up the right and Revell got in at the near post but his header was held by the keeper. The wind was blustery and swirling and affecting judgement at times - Millers fans were just glad they weren’t at Don Valley!
Arnason, so calm on the ball, backed up an attack and slid a pass through for Tubbs and his snap shot almost got through Walker, the ball deflecting away off his leg and may have been via the near post too.
Rotherham just needed that additional goal to sort this game out but were having more defending to do this half as the visitors sought an equaliser.Mills sorted out one attack and then O’Connor was back to block a shot from Morrison.
Revell went full length to try and turn in a Frecklington cross, and it was clear the striker was desperate to get on the end of a chance.
It’s not often you get a crowd singing about the physio but the North End had a chorus of... “There’s only one Denis Circuit” and then “Denis, Denis give us a wave...” and the popular physio obliged from the dug out! It would have made his day on his 700th appearance.
Right at the end of stoppage time, LEE equalised with a header that hit the bar and bounced inches over the line, to leave the Millers sickened.