Swansea City’s unbeaten run came to an end as promotion hopefuls Nottingham Forest ran out convincing winners at the City Ground.

The Swans had been level at the break, Michael Obafemi firing home his 12th goal of the season to equaliser after a bizarre opener from Jack Colback for the hosts.

But, having battled well and offered a threat to get in all-square at half-time, the Swans undid their good work within seven minutes of the restart, conceding a brace of goals to Sam Surridge from a corner and a counter-attack respectively.

That left the visitors chasing the game, and Surridge fired home Forest’s fourth from another counter to complete his hat-trick, before Alex Mighten rounded off the scoring.

It marked Swansea’s first defeat since the loss at Blackpool in mid-March and was a first defeat in 10 Championship games, but nevertheless Russell Martin will surely be frustrated at how his side allowed the game to get away from them early in the second period regardless of Forest’s own superb run as they chase automatic promotion.

The Swans had shown one change from the draw against Bournemouth, Cameron Congreve making his first start with injury victim Ben Cabango absent.

Amidst a febrile atmosphere, it was the Swans who had the first effort on goal, Cyrus Christie stinging the palms of Brice Samba, who could not hold at the first attempt, with an angled drive.

But the Swans soon survived a scare as Sam Surridge got away from Joel Latibeaudiere and his pull-back looked set to allow Philip Zinckernagel a tap in, only for Ryan Manning to block on his own line.

Christie then made a magnificent block as James Garner arrived on to a Djed Spence pull-back before Surridge sent a tame volley into Andy Fisher’s arms after springing the offside trap.

Some neat link play allowed the Swans to get around the Forest press in the 17th minute, with Joel Piroe having a shot saved by Brice Samba after Matt Grimes’ fierce original effort had been blocked.

The Swans threatened again, Christie stealing in down the right before the following corner saw Congreve’s delivery unconvincingly punched by Samba.

But the visitors then fell behind in bizarre circumstances.

Christie and Fisher could not deal with a Spence cross, and there were a pair of red shirts quickly in attendance to try and force the ball home.

Referee Graham Scott blew and awarded a penalty for handball against Christie, and without hesitation pulled out a red card.

However, interventions from the assistant referee and fourth official saw a goal given and credited to Colback and the penalty and sending off overturned, with the reasoning seeming to be that the ball had crossed the line before the Swansea player handled.

However, Scott then booked Christie to complete a strange few moments.

But the Swans hit back superbly, Obafemi controlling a Grimes pass to sit down his marker and fire home.

It was no less than the visitors deserved for the bravery they had shown on the ball but they still needed Fisher to produce an outstanding stop as Joe Worrall got ahead of his man at a corner to steer a firm effort at goal.

However, the game was becoming increasingly niggly and threatened to spill over as half-time approached.

Fisher was producing a tremendous performance and a superb double save kept the scores level.

Firstly, he somehow tipped Surridge’s header onto the post, and then used his feet to deny Yates from point-blank range seconds later.

Surridge then spurned a sitter after Zinckernagel had got into space down the left and laid on an astute pass before Samba himself made a smart stop to keep out Obafemi’s stinging drive as an absorbing half ended level.

But it was not level for long in the second half, Surridge won a corner and the resulting delivery was headed home by the striker at the far post.

And Surridge quickly grabbed another as Swansea were caught out on the counter-attack, with Garner driving forward and teeing up the forward to curl an effort high into the far corner of the net.

It was a nightmare start to the second half and Forest now firmly had their tails up.

Martin sent on Olivier Ntcham and Jamie Paterson from the bench for Manning and Congreve moments before Fisher brilliantly denied Surridge a hat-trick.

Ntcham fired wide at the other end before Naughton became the latest to make a key intervention for the visitors as he slid in as Sturridge pulled the trigger inside the box.

Wolf then tricked his way past Spence to get to the byline in the area, but could not pick out a white shirt.

And Swansea got punished on the counter again when McKenna was allowed to easily pick his way out of defence.

Forest quickly motored upfield and, after Spence’s mis-hit cross struck the bar, Surridge volleyed in the rebound to put the game to bed.

Wolf had an effort saved but Forest would have the last word as Christie was unable to deal with a long ball down the middle and Mighten muscled in to guide the ball into the net.

Swansea City: Andy Fisher; Joel Latibeaudiere, Kyle Naughton, Ryan Manning (Olivier Ntcham 58); Cyrus Christie, Flynn Downes, Matt Grimes (captain), Hannes Wolf; Joel Piroe (Jay Fulton 78), Cameron Congreve (Jamie Paterson 58); Michael Obafemi.

Unused Substitutes: Ben Hamer, Korey Smith, Nathanael Ogbeta, Kyle Joseph.

Nottingham Forest: Brice Samba, Djed Spence, Joe Worrall (captain), Jack Colback (Richmond Laryea 85), Philip Zinckernagel (Joe Lolley 69), Sam Surridge (Alex Mighten 77), Brennan Johnson, Ryan Yates, Scott McKenna, Steve Cook, James Garner.

Unused Substitutes: Ethan Horvath, Tobias Figueiredo, Cafu, Dale Taylor.

Referee: Graham Scott