On-the-whistle report: Middlesbrough 0 Rotherham United 3

Warne was up against former Millers manager Neil Warnock in the dugout and saw his side score in each half at the Riverside Stadium to further boost their bid for second-tier survival.

Rotherham fully deserved their victory as scorers Matt Crooks and Michael Smith left the Boro backline in tatters with stunning, hard-running displays.

New boy Ryan Giles came on for his debut and instantly made his mark by adding a third goal near the end.

The triumph - the Millers' first at Middlesbrough since 1965 - moved Warne's third-bottom men to within two points of Derby County with two games in hand and gave them a haul of seven points from their last three matches.

Warnock will have been fuming at his own side's display but must have admired what he witnessed from the club where he is a hero for masterminding Championship safety in 2016.

On this evening, Warne and his side were all heroes.

Rotherham were close to taking an early lead when Crooks' touch sent Michael Smith running in on goal  but the striker pulled his low effort from just outside the area inches wide of the post.

Crooks was adamant he should have been awarded a penalty on 20 minutes when he and Paddy McNair came together in the Boro box. The Millers man hit the deck a few yards from goal and was outraged when the referee gave the foul to the home side.

Five minutes later, the attacking midfieler should have put his side ahead. He did brilliantly to hound Jonny Howson out of possession and then spoiled all his good work by steering the ball wide when he had only goalkeeper Marcus Bettinelli to beat.

The pace and power of the Smith/Crooks partnership was troubling Middlesbrough who looked threatening at times but could muster nothing more than a skied shot from Sam Morsy.

As the interval approached, Crooks spectacularly made amends for his earlier miss, volleying the ball into the bottom corner from the edge of the box after Smith's attempt had been blocked.

It was a lead the Millers fully merited and Smith would have made it 2-0 right on time with a looping header had it not been for Bettinelli's flying, full-stretch intervention.

Rotherham were without midfielder Dan Barlaser who had previously made every matchday squad following his permanent switch from Newcastle United in October.

That meant a first taste of action for Shaun MacDonald since he broke his leg at Stoke City in late October.

Giles, signed on loan signing from Wolverhampton Wanderers the day before the contest, was on an eight-man bench.

Boro had obviously been read the Warnock riot act at half-time and Manchester City loanee Patrick Roberts fired over soon after the restart.

However, it was the Millers who were next to threaten as Bettinelli spilled Jamie Lindsay's low free-kick from outside the area and Smith almost took advantage.

Just past the hour mark, Boro broke quickly through Duncan Watmore and Jamal Blackman produced a superb reaction save to deny Morsy.

But the Millers fought back and a huge penalty shout went unanswered when substitute George Hirst looked to have been impeded seconds after his 68th-minute introduction.

Eleven minutes later, the referee finally acted on a spot-kick appeal, agreeing that Michael Ihiekwe had been upended by Bettinelli.

Up stepped Smith to coolly fire Rotherham 2-0 in front with his fifth goal in his last six league games.

From then on, they comfortably held Boro at bay and debutant Glles struck a clinical third in time added on four minutes after his arrival.

A wonderful performance on an unforgettable night.

Goals: Crooks 43, Smith pen 79, Giles 90+2 (Rotherham).

Middlesbrough (4-2-3-1): Marcus Bettinelli; Djed Spence (Hayden Coulson 68), Nathan Wood, Paddy McNair, Marc Bola (Marvin Johnson 83); Jonny Howson, Sam Morsy; George Saville, Patrick Roberts (Lewis Wing 68), Duncan Watmore (Ashley Fletcher 83); Britt Assombalonga (Chuba Akpom 68). Subs not used: Jordan Archer, Grant Hall, Hayden Hackney, Issac Fletcher.

Rotherham (3-5-1-1): Jamal Blackman; Michael Ihiekwe, Richard Wood, Angus MacDonald; Matt Olosunde, Shaun MacDonald (George Hirst 68), Jamie Lindsay (Ryan Giles 88), Ben Wiles, Wes Harding; Matt Crooks (Clark Robertson 85); Michael Smith. Subs not used: Viktor Johansson, Adam Thompson, Curtis Tilt, Trevor Clarke, Freddie Ladapo.

Referee: Michael Salisbury (Lancashire).