Bristol City 4-2 Cardiff City
Mark Perrow reports from Ashton Gate
Martyn Woolford was the hero of the Severnside derby to send City - temporarily at least - to the top of the npower Championship.
The day will be remembered for Sam Baldock's debut goal after he arrived from the bench, but Woolford's brace either side of half-time was pivotal.
Stephen Pearson had given City the lead on 32 minutes, while half-time substitute Joe Mason pulled one back for Cardiff between Woolford securing a two-goal lead on two occasions.
Heidar Helguson's 82nd minute strike looked set to ensure an edgy finish to a fantastic game, but Baldock - the man on everyone's lips after his unexpected Ashton Gate unveiling in the week - raced clear to wrap up the three points and send City to the league summit.
Derek McInnes recalled Mark Wilson to his starting line-up at the expense of Richard Foster - the former Celtic right-back having missed the midweek demolition of Crystal Palace through illness.
The City boss resisted the temptation to hand big money signing Baldock his first start in an otherwise unchanged starting eleven again led by Jon Stead and Ryan Taylor up front.
Cardiff looked the more probing in the early exchanges and soon tested former Bluebird Tom Heaton in the City goal with a rasping 25-yard drive from Peter Whittingham.
But the hosts responded with a strong run from Woolford, who fed Stead. He in turn saw Albert Adomah perfectly placed, but the pass did not have the pace to run across the body of the winger, who had to stab at the ball with the outside of his right foot and saw his shot disappear high and wide of goal.
By the midpoint in the first half City were well on top, and the front two almost combined to goalscoring effect with Taylor just unable to divert Stead's deep cross on target.
Cardiff remained a counter-attacking threat, and Helguson broke free of the City backline to set up debutant Tommy Smith, whose shot was blocked by what suspiciously looked like a raised hand from Cole Skuse, albeit at virtually point-blank range.
The visitors were contributors to their own downfall 13 minutes before half-time, as midfielder Aron Gunnarsson gifted the ball to Stead. The former Ipswich Town striker again found the ever-willing Adomah, whose square pass was clinically dispatched by Pearson on his supposedly weaker right foot from 12 yards.
Four minutes later, Whittingham's daisy-cutter caught a trailing leg on its way behind for a corner, from which the Cardiff midfielder's delivery was headed down into the ground and up on to Heaton's crossbar before the keeper clawed the ball to safety.
But Woolford sunk the knife into the Bluebirds' hopes of regrouping at the interval with a second in stoppage time. Fed by Stead, the former Scunthorpe United man raced through to slot the ball with ease past Cardiff number one David Marshall to leave City in dreamland.
McInnes' men also started the second half brightly, but Mason grabbed a goal back 12 minutes after coming on. Whittingham's corner was initially cleared off the line before the former Plymouth Argyle forward glanced in from close range to hand his side a lifeline.
The visitors were upping the ante, with every Whittingham set piece causing problems, but Baldock was introduced for Stead on 65 minutes to give Cardiff something to think about in the other direction.
The substitution almost paid immediate dividends, as the diminutive striker darted into space on the City left, cut inside and tried to reverse his shot back across Marshall only to brush the sidenetting.
At the other end Cardiff's best chance for an equaliser fell the way of the right man, but Whittingham drove his shot into the turf and the ball bobbled away beyond Heaton's left-hand post with the keeper beaten.
Baldock's arrival had reignited the Ashton Gate crowd, and when Woolford set him up a debut goal looked on the cards. Instead City's new number seven sidefooted against the post, but Woolford was on hand to convert the rebound for his second.
Cardiff still were not finished, as Helguson tucked away their second from close range after more good work from Mason eight minutes from time, but Baldock put the game to bed five minutes later with an accomplished placed finish beyond Marshall's left hand.
It ensured City of their first back-to-back wins, scoring four goals in each, since November 2004.