A sixth win in eight league games lifts United up to sixth and within three points of champions Manchester City in fourth.
Despite shelling out over £1 billion ($1.26 billion) on new players in three transfer windows, Chelsea remain down in 10th.
Hope that the arrival of Pochettino would usher in a quick turnaround in fortunes has proved short-lived as the Argentine has won just five of his first 15 league games in charge.
Ten Hag had been under increasing scrutiny amid reports of dressing room disquiet.
But his big decision to drop Marcus Rashford to the bench among four changes paid dividends as the Dutchman was rewarded with a far more energetic and enterprising display.
Chelsea had goalkeeper Robert Sanchez to thank for getting in level at the break.
United had 18 shots on goal before half-time — the most Chelsea have faced in one half in the Premier League for 20 years — but only had one goal to show for it.
A VAR intervention to award a penalty after Enzo Fernandez stood on Antony’s foot gave the home side a glorious chance to open the scoring.
But Sanchez flew low to his right to parry Bruno Fernandes’ spot-kick and Alejandro Garnacho blazed the rebound over.
United’s determination to flood forward was also leaving gaps for Chelsea to exploit on the counter-attack.
Mykhailo Mudryk struck the outside of the post and the Ukrainian should have sent Raheem Sterling clean through on goal but for a poor pass that ruined another promising break.
Sanchez was called into action once more to save a powerful effort from Garnacho, while Antony’s wait to break a 24-match run without a goal goes on as he fired tamely into the Spanish international’s arms.
Chelsea and Sanchez’s resistance was finally broken when McTominay swept home his fifth goal of the season to become United’s top scorer in the Premier League on 19 minutes.
The Scottish midfielder should have had a second moments later when his header from point-blank range and follow-up effort were both excellently saved by Sanchez.
And the hosts were made to pay as Chelsea levelled before half-time.
Cole Palmer was allowed to jink his way along the edge of the box and slotted into the far corner beyond Andre Onana’s grasp.
Chelsea could have turned the game on its head early in the second half had Nicolas Jackson not wasted a glorious chance when he headed over unmarked from a corner at the back post.
But United were quickly back on the front foot.
Garnacho continued to curse his luck as a curling effort drifted inches wide.
However, the Argentine had a hand in the winning goal as his cross was powered in by McTominay’s header 21 minutes from time.
McTominay should have a hat-trick when he skewed horribly wide with just Sanchez to beat.
United’s profligacy gave Chelsea the chance to snatch a point late on when Armando Broja headed against the crossbar.
But that would have been more than the Blues deserved as Pochettino struggles to turn Chelsea’s abundance of young talent into a functioning unit.
Nat. Standard3 months ago
Minister, Idris, challenges Senate to review outdated laws to improve performance in the information sector
Education2 months ago
Hours after suspending accreditation of degree certificates from Benin Republic, Togo, FG set to extend sanction to Uganda, Kenya, others
Sports2 months ago
Ayanwale emerge winner of Seyi Tinubu Table Tennis Challenge as Ogunlende, Bolowotan task youths on sports involvement
NCC4 weeks ago
Telecom Indicators: Nigeria sees steady increase in active voice and internet subscriptions, drop in teledensity
Agribusiness1 month ago
Borno government tasks media on sustaining public interest, core values
Aviation4 weeks ago
NCAA cautions pilots, airlines as NiMet alerts Nigerians of dust haze
Aviation4 weeks ago
Libya reportedly deports over 320 illegal migrants to Nigeria
Aviation4 weeks ago
Accurate weather forecasts essential to solid minerals development – NiMET DG