David McGoldrick put the Sky Blues in front but Robin Shroot equalised in the first half and substitute Marcus Haber sealed the points for the visitors with 20 minutes at the Ricoh Arena remaining after the home side had looked by far the stronger of the two teams in the first half.
The Sky Blues were in front after just 11 minutes, when McGoldrick, on loan from Nottingham Forest, won a header three yards outside the area, brought the ball down well and curled home a right-footed effort past Chris Day.
But the visitors were level 10 minutes later, when they broke impressively and Luke Freeman's shot was parried by Joe Murphy, but Shroot followed up to convert. Coventry had further cause for complaint in the 27th minute when Stephen Elliott netted but was harshly judged to have been offside.
Neither side grabbed the game by the scruff of the neck at the start of the second half, but Stevenage made three changes and they paid dividends when Haber headed powerfully home in the 71st minute - sealing a third successive away win.
Three goals in 11 second-half minutes helped Portsmouth to their first league win of the season as they triumphed 3-0 at nine-man Crawley.
Substitute Ashley Harris struck in the 74th minute to put Pompey ahead before Luke Rodgers and Izale McLeod completed the away side's victory - ending Town's 100% home form in front of a record 5,058 crowd at the Broadfield Stadium.
Crawley finished the match with just nine players after Josh Simpson and Hope Akpan were both sent off for two bookable offences.
Akpan had gone close for Crawley with a dipping right-footed volley from 20 yards before Gary Alexander almost steered home a teasing Nicky Adams cross as the Reds began brightly. But in the 41st minute referee Darren Deadman showed a red card to midfielder Simpson after two separate fouls on McLeod.
Team-mate Akpan was then given his marching orders in the 71st minute before Harris quickly tapped Pompey into the lead after a cross from Adam Webster.
Rodgers doubled the lead with a stunning 20-yard free-kick in the 83rd minute before McLeod rounded Crawley `keeper Paul Jones to complete his side's victory two minutes later.