Lincoln City gained the upper hand on their former manager Michael Skubala as they beat his Bristol City side at Ashton Gate.
Skubala left the Imps in May, just over four weeks after guiding them to the League One title and promotion to the Championship, and the Lincoln starting XI included nine players who featured under him last season.
Among those was Freddie Draper, who capitalised on a defensive mishap from the Robins early in the second half to score the only goal of the match.
The result sees Lincoln leapfrog Bristol City in the table, up to eighth, as they extended their unbeaten league run to five consecutive games.
This was the first league meeting between the two clubs since April 1986, and while Bristol City enjoyed double the possession and twice as many shots, they lacked quality in front of goal and faced a solid Lincoln defence.
Their best pressure came during the first 20 minutes of the first half, when Rio Cardines curled multiple set pieces into the box that his teammates were unable to finish from.
Imps keeper George Wickens tapped a Hirakawa effort over, Lorent Tolaj headed onto the crossbar, and Gibson Yah headed wide from a few yards out, before Tolaj missed the best chance of the half when the ball was recycled out to him unmarked in the box and he missed the target.
Lincoln were limited to just one real effort, as Chiedoziwe Ogbene dived onto a Dom Jefferies cross and put the ball the wrong side of the post.
The visitors started brighter after the break and Ogbene broke onto a pass from Draper into space and forced keeper Sam Tickle into a save.
Shortly afterwards they took the lead, pouncing on a defensive howler as Ben House got his boot on a sloppy Rob Dickie backpass to Tickle, who had come off his line.
House tapped the ball on to Draper, and he had an empty net to slot into for his second goal in two games.
Hirakawa had an opportunity to draw the hosts level seven minutes later, only for Wickens to react quickly to deny him, and Bristol City's misery was compounded when centre-back Dickie was stretchered off with a serious-looking knee injury.
Lisav Eissat headed wide and Dom Ballard also struck wide from the edge of the box in the closing minutes as Lincoln recorded a fourth Championship clean sheet of the campaign.
