Conor Chaplin scored a stoppage-time winner as Portsmouth stunned Middlesbrough to boost their Championship survival hopes and deal a huge blow to the Teessiders' automatic promotion bid.

On-loan Ipswich forward Chaplin struck in the seventh minute of time added on from Adrian Segecic's corner to score from Portsmouth's only shot on target at the Riverside Stadium.

Middlesbrough have slipped to fourth place in the table and are three points behind second-placed Ipswich, having played two games more.

Chaplin's late, late winner will have pleased his parent club but perhaps not as much as it delighted his current side - it hauled Portsmouth back out of the bottom three and they are a point clear of Oxford with a game in hand.

The defeat further damages Middlesbrough's hopes of going up automatically - Kim Hellberg's side have now managed just three points from their past six games, their worst run of the season.

This was a proper smash and grab raid by Portsmouth and as poor as Middlesbrough were, they still managed eight shots on target.

But they could not beat Pompey goalkeeper Nicolas Schmid as John Mousinho's Pompey side ended their eight-game run without a win at a critical time.

Schmid saved a shot from Alan Browne and a weak header from Dael Fry in a fairly pedestrian first half.

Hellberg tried to inject some vigour into his Middlesbrough side, bringing on Sontje Hansen and Luke Ayling at half-time, and Riley McGree had a shot from a narrow angle saved by Schmid.

The goalkeeper was in no mood to be beaten and he denied Browne, when the midfielder attempted to chip him, before he frustrated McGree again.

Middlesbrough pressed desperately to find a way through and Hansen had a shot saved before Andre Dozzell headed his second effort off the line in the first minute of stoppage time.

The home fans urged their side on but it was Portsmouth who broke the deadlock thanks to Chaplin's second goal of the season, a strike that could have a massive impact at both ends of the table come the final reckoning.

Middlesbrough boss Kim Hellberg told BBC Radio Tees:

"We were not good enough. We lacked energy, quality and structure.

"That is different from other games. Sometimes we played well without the result, today we were not good enough except defensively. It makes you flat and disappointed.

"We didn't have our best game. We played three in a week, some games are better than others. We didn't defend the second phase of the corner well enough. That has been a theme of the home games.

"Six in a row without a win from a team that plays good football. That is not a feeling you want, we are trying to make it right but we are not succeeding. That is my responsibility."

Portsmouth manager John Mousinho told BBC Radio Solent:

"Managing to score with the last kick in the circumstances is right up there [for most dramatic wins of my career].

"We did what we had to do today. We stayed in the game and had good opportunities on the break in the second half, we didn't have the confidence or belief.

"When you don't have a lot of the ball it can sometimes be a bit panicked when you win it back.

"Some of the last-ditch defending [was brilliant]. It was a whole team effort."