Derby’s promotion hopes were dealt a major blow as they suffered a narrow 1-0 League One defeat at midtable Northampton.

The Cobblers’ first win in six games – and their first ever over Derby – came thanks to Sam Hoskins’ first-half strike, his 15th goal of the season.

Derby dominated possession early on and they should taken a 20th-minute lead but Martyn Waghorn side-footed the ball over with the goal at his mercy.

Northampton struck against the run of play midway through the first half when Louis Appere chased down a long ball and showed brilliant vision to pick out Hoskins, who volleyed first time into the bottom corner.

The visitors responded well but they could not find a leveller before half-time despite Ebou Adams twice going close, first denied by Sam Sherring’s goal-line clearance and then heading over when well placed.

Nathaniel Mendez-Laing almost converted Kane Wilson’s cross after the restart before Manny Monthe hit the post at the other end.

Derby applied plenty of late pressure but could find no way through Northampton’s resilient rearguard and their misery was compounded by a straight red card for Sonny Bradley in stoppage-time.

Paul Warne brushed off his Derby side moving back into the top two of Sky Bet League One after a convincing 3-0 win at Bristol Rovers.

The Rams boss explained that if his team keep winning, following the club’s sixth victory in their last nine games, then they need not worry about what any of their promotion rivals are doing.

Dwight Gayle opened the scoring in the 55th minute, bundling in after Tom Barkhuizen’s shot had hit the crossbar and bounced on the goal-line.

Barkhuizen guided in a first-time effort from a Nathaniel Mendez-Laing pass to double their lead before substitute Martyn Waghorn made sure of the result when he poked in from close range in the 89th minute.

“We just keep saying to the lads ‘don’t look at the league table, just keep playing your best football for 10 games and see where we’re at’,” said Warne.

“Everything matters – I’ve said that from day one. I was talking to the lads today that it’s 250 days since we started this campaign and the pre-season, and everything matters, every tackle you make, every tackle you miss.”

Warne’s side have now won back-to-back league games 3-0 and his side may be finding form at the right time. The former Rotherham boss is eager for his side to find yet more consistency.

“You’ve just got to be bang on the money if you’re going to be successful and today this performance is already over,” he added.

“I want the lads to enjoy it for about half an hour, but then we’ve got to do it again Tuesday and then again Saturday. You’ve got to be relentless.

“My only slight criticism is that at times today we let them off the hook where we could have really finished them off. But I’m really pleased with the goals and the clean sheet.”

Bristol Rovers counterpart Matt Taylor recognised the quality of the opposition, hailing Derby as the best team in the division before the match.

Afterwards, the Rovers boss was particularly unhappy with how his side dealt with dead-ball situations.

“Set-pieces were frustrating as we’ve got a couple of first contacts on the long throw and the corner [that led to the opening goal] and got there first, but if we get there second then it’s more of a scramble. We have to be better.

“The next two [goals] come when we’re in possession of the ball and the third is when we’re really chasing the game. But that was a little bit of a reflection of us today. Our ball use wasn’t good enough today.

“In terms of the individual aspects they ‘manned’ the game today – they taught us a lesson in how to manage the game and how to manipulate certain situations.”

Dwight Gayle scored his second goal for Derby as the striker boosted the Rams’ drive for a Sky Bet League One automatic promotion place in a 3-0 win at Bristol Rovers.

The former Newcastle forward opened the scoring in the 55th minute before Tom Barkhuizen added a quick second three minutes later.

Martyn Waghorn wrapped up the three points late on, which saw them climb up to second in the table.

A poor clearance from Lewis Gordon fell to Barkhuizen, who swept against the crossbar, with 34-year-old Gayle reacting quickest to prod in from inches out as the ball bounced on the goal-line.

Derby doubled their lead when Nathaniel Mendez-Laing broke forward and played the ball across for Barkhuizen to put a powerful first-time strike into the top corner.

Antony Evans curled just over the bar with 25 minutes left to play and Eiran Cashin had to clear off the line as Scott Sinclair advanced on goal with Rovers pushing to come back into the game.

But the Rams stood firm, sealing the victory with a minute to play as substitute Waghorn tapped in Korey Smith’s low cross.

Martyn Waghorn scored for the second time in four days to give Derby a 1-0 win over Fleetwood that ended a run of three home defeats.

Derby swarmed all over Fleetwood from the start and got the goal their dominance deserved in the 23rd minute.

Conor Washington’s shot was deflected to Waghorn, who swivelled to send a low shot inside Jay Lynch’s left post.

Danny Mayor fired over as Fleetwood responded and Derby survived a scare in the 45th minute when Jayden Stockley headed against Joe Wildsmith’s right post.

It was a reminder that Derby needed a second and they went close several times at the start of the second half through Liam Thompson and substitute James Collins.

But Fleetwood almost equalised in the 72nd minute when Promise Omochere’s header was tipped against the bar by Wildsmith, who pushed away a Junior Quitirna shot six minutes later.

Quitirna flashed a ball across the six-yard box in stoppage time but Derby held on for their second win of the season.

Mark Harris’ double gave Oxford a 2-1 win at Derby.

Harris scored in each half before Martyn Waghorn replied late on for the home side.

Oxford had the first shot on target in the 17th minute with Marcus Browne forcing Joe Wildsmith into a diving save after good build-up play.

The visitors deservedly went ahead in the 32nd minute when Curtis Nelson gave the ball away and Cameron Brannagan played in Harris to fire into the top-right corner.

Derby put Oxford under pressure early in the second half but almost conceded again in the 64th minute when Browne set up Billy Bodin whose low shot brought a great save from Wildsmith.

Oxford’s pace and quick passing was rewarded in the 72nd minute when another slick move was converted by Harris low to Wildsmith’s left.

Derby responded in the 87th minute after Oxford failed to clear a long throw and Waghorn scored from 15 yards but it was not enough to save them from a second home League One defeat.