Leon Best broke the deadlock with a thunderous eighth-minute free-kick that proved to be the only real moment of quality in an otherwise tame first half in South Yorkshire.
The second 45 minutes proved to be a much livelier affair, though, with Tykes left-back Robert Kozluk receiving his marching orders for a second yellow card in as many minutes just before the hour mark.
And it was left for Clinton Morrison to make sure of all three points for the visitors when he volleyed home nine minutes from time to grab his third goal of the season so far.
The one positive on a miserable afternoon for Barnsley came in the form of Iain Hume's first return to action as a second-half substitute following the fractured skull he received against Sheffield United last November.
The result leaves the Sky Blues with maximum points after their 2-1 victory over Ipswich on the opening weekend, while Simon Davey's Barnsley have a draw to show from their first two forays into the 2009/10 campaign.
Despite the Tykes making all of the early running it was Coventry who took the lead in stunning style with virtually their first attack of the game.
Sky Blues forward Morrison was brought down in a central position on the edge of the area and strike partner Best stepped up to smash the resulting free-kick into the roof of the net, leaving goalkeeper Luke Steele with no chance.
Normal service was resumed after the opener as Barnsley enjoyed plenty of possession, but they failed to really do much with it, a disappointing lack of quality in their final ball and some wayward passing letting them down.
Clear-cut chances were at a minimum as the first half progressed, Sammy Clingan curled a set-piece off target while fellow midfielder Isaac Osbourne hooked horribly wide shortly before the break as Coventry looked slightly more threatening when they did venture forward.
Aron Gunnarsson could have all but sewn the game up for the visitors with 15 second-half seconds on the clock, but he failed to hit the target from around 25 yards having waltzed through the Barnsley midfield straight from kick off.
Coventry continued the second half in positive fashion and Steele did well to parry Gunnarsson's effort to safety, before Morrison put a half chance over the crossbar in the 53rd minute as the Tykes keeper dropped a routine ball into the penalty area.
The home side's afternoon went from bad to worse not long after as Kozluk received his second yellow card in the space of two minutes for a bad foul on Gunnarsson.
But the hosts responded well and Jacob Butterfield drilled their best chance of the game narrowly wide shortly after, while Iceland midfielder Gunnarsson again fired wide at the other end when he should really have done better.
Hume made his return to action as a 67th-minute substitute for Jon Macken but Coventry started to turn the screw as the game entered the closing stages.
And Morrison wrapped up the points nine minutes from time with a well-taken volley from Osbourne's deep cross.