Local boy Joe Bryan was the storybook hero on derby day at a bouncing Ashton Gate.
City seemed in control of their own destiny from the moment Jay Emmanuel-Thomas struck a bolt from the blue in the twelfth minute, but set-piece frailties reared their ugly head, as Rovers conjured an equaliser when Mark McChrystal headed home Lee Brown’s free kick.
But Bryan was to be the headline act, as he struck the killer blow 14 minutes from time to ultimately decide an absorbing contest.
Sean O’Driscoll made five changes to his side held to a 1-1 draw at Gillingham, handing a debut to James O’Connor at centre-back in place of the injured Derrick Williams, and first starts to Nicky Shorey and Marlon Harewood – the latter as captain in place of benched top scorer Sam Baldock.
Elsewhere, Joe Bryan returned on the left side of midfield, while Greg Cunningham, Marvin Elliott and Wes Burns were all absent due to international duty.
After a typically cagey derby day start, Emmanuel-Thomas sent Ashton Gate into ecstasy with a stunning opener.
Collecting the ball on the half turn, the unpredictable forward pushed the ball out of his feet and unleashed an unstoppable 30-yard shot which flew into the top corner of the net.
Rovers keeper Steve Mildenhall dived but, in truth, two men would have struggled to keep it out, such was the power of the strike.
The visitors showed some threat in the immediate aftermath, with City old boy David Clarkson dragging a tame shot wide from the edge of the box, before Tom Lockyer tested stand-in stopper Elliot Parish for the first time.
At the other end, Aden Flint went close from a corner, before the Robins’ defence came under similar scrutiny when Oliver Norburn’s flat delivery was headed over by John-Joe O’Toole.
But City still looked the superior outfit, and some Bryan trickery saw the winger skip inside his man and lay the ball off for Harewood, whose low drive forced a tremendous save from the strong right hand of Mildenhall.
But Emmanuel-Thomas was the star attraction. With the home faithful baying for him to shoot when he picked the ball up 25 yards from goal, he instead ventured on a jinking run to beat two Rovers defenders before seeing his effort deflect just out of reach of the incoming Harewood in the box.
O’Driscoll’s side looked in control, but Marlon Pack was guilty of overplaying in dangerous territory, presenting Matt Harrold with a free shot from the edge of the penalty area, but the striker was hurried into an attempt more resembling of a backpass than an equaliser.
Meanwhile, Bobby Reid, one of two Bristolians in the home ranks, almost wrote his name into derby folklore when his inventive chip was only denied by the crossbar.
Mildenhall was still rooted to the spot after a couple of stepovers bought the City Academy product a yard of space on the right corner of the box.
City were pushing for a second, and Harewood nearly provided it shortly before the interval with a fizzing low drive that just skimmed the left post.
Although it was hardly one-way traffic in their favour, Rovers did start the second half with greater intent.
Winger Ellis Harrison was looking lively down the left flank and there was undoubtedly fresh impetus about the visitors, and when Pack gave away a soft free kick just before the hour mark, the Gas seized their moment.
When Brown swirled the set-piece into the danger area, McChrystal rose highest to head the ball back across goal and into the net – just – via the angle of post and bar.
City had fallen flat, and O’Driscoll responded by unleashing Baldock for Harewood with little more than 20 minutes standing between the two rivals and a nerve-shredding penalty shoot-out.
Just as chances seemed few and far between, Emmanuel-Thomas ironically set pulses racing with a casual saunter into Rovers territory, culminating in a placed shot down to Mildenhall’s left.
The keeper succeeded in parrying the ball wide of the lurking Baldock, but Bryan was perfectly placed to step on to the ball and send a precise right-footed shot into the top corner.
It was another superb finish, and one fitting to win such a tie.
But Rovers had their chances. Norburn shot wide from distance before missing a gilt-edged chance when Parish parried a fierce Harrison drive into his path.
His shot was high, but City were on cloud nine.