The Sky Blues midfielder joined Sheffield United on the eve of the game but his former side registered their first win of the campaign courtesy of instinctive goals in either half from Matty Godden and club record signing Haji Wright.
Darragh Lenihan’s stoppage-time own goal capped a miserable afternoon for Michael Carrick’s side who are winless in their last seven Championship games – four of those coming against Coventry who beat them in last season’s play-off semi-final.
It’s the first time Boro have lost their opening two league games since 2007.
- Relive Coventry v Middlesbrough as it happened
It took just 11 minutes for the hosts to go ahead when Godden was quickest to react and tuck into the bottom corner after Josh Eccles’ ball into the box deflected off a defender.
Godden was denied a second when his angled strike was saved by Seny Dieng on 22 minutes, but Milan van Ewijk – starting in place of Hamer – could only drag the rebound past the post, and Ellis Simms had two fizzers stopped by Dieng.
Boro improved after the break and summer signing Morgan Rogers weaved his way forward from halfway and into the box before drilling past the post when well-placed.
Isiah Jones then slammed into the side-netting from an angle before Rogers cut back for the unmarked Samuel Silvera who blazed over with Ben Wilson’s goal at his mercy.
However, American Wright came off the bench on 66 minutes and made the game safe within four minutes, slamming home the loose ball after a corner caused chaos on the Boro line.
At the other end, Wilson parried a Rogers cross at the near post, only for the ball to loop wide of the unguarded net off the unfortunate Matt Crooks.
There was still time for Godden’s attempted cross from the right to glance inside the near post off Lenihan early in eight additional minutes.
Boro scored 84 goals last season, but have failed to score in their opening two league games, with 28-goal top-scorer Chuba Akpom missing from today’s squad after a pre-season impacted by injury and transfer speculation.