Josh Coburn’s first-half strike clinched play-off chasing Millwall a 1-0 win at Bramall Lane and dented Sheffield United’s automatic promotion chances.

Millwall turned in one of their best away displays of the season to frustrate the Blades and Coburn’s thumping finish lifted the Londoners to within three points of the top six with five games to play.

Blades substitute Jesurun Rak-Sakyi twice went close to equalising while Chris Wilder’s side, who slipped to their eighth league defeat of the season, created a string of scoring chances.

But the Lions, for whom Mihailo Ivanovic should have doubled his side’s lead, turned in a never-say-die defensive display and were a constant threat on the counter.

Coburn headed an early free-kick over for Millwall and Blades forward Rhian Brewster’s first-time effort span narrowly wide from a corner.

The visitors, who began the day in ninth place, six points off the play-offs, struck the opening goal in the 21st minute, just when the Blades appeared to be building momentum.

Billy Mitchell’s low ball into the box picked out Casper De Norre and he helped the ball on to Coburn, who slammed home his fifth league goal of the season beyond Blades goalkeeper Michael Cooper.

Ben Brereton Diaz went close to an early response for the home side when his glancing header forced a fine reaction save from Lukas Jensen.

Home fans’ frustration at going a goal down reached fever pitch when referee Sam Allison waved play on after Millwall skipper Jake Cooper had wrestled Anel Ahmedhodzic to the ground.

The Blades created several half-chances before the break but Millwall, who continued to carry a threat on the break, held on to their slender lead at half-time.

Rak-Sakyi replaced Brereton Diaz at the break and he should have equalised for the Blades just after the restart, only to miscue his shot in front of goal from Harrison Burrows’ cross.

Rak-Sakyi turned sharply to fire straight at Jensen soon after as the Blades turned the screw in search of an equaliser.

Ivanovic then missed a golden chance to put Millwall 2-0 up, shooting straight at Cooper after Coburn’s cross had left him one-on-one with the goalkeeper.

Jensen saved well from Gus Hamer’s fierce low effort before Blades boss Wilder sent on Vini Souza, Callum O’Hare and Tom Cannon for Hamza Choudhury, Brewster and Tyrese Campbell.

Cannon lashed in a low shot, well held by Jensen, as the Blades ramped it up with 10 minutes to go and Rak-Sakyi’s close-range effort rolled agonisingly wide as Millwall held on and Wilder’s side slumped to back-to-back defeats.