Andrew Nelson's debut goal earned Dundee a 2-1 win at Hearts and ensured his new side moved off the foot of the Ladbrokes Premiership.
The 21-year-old, who joined the Dark Blues from Sunderland for an undisclosed fee earlier this month, lashed a low drive beyond goalkeeper Colin Doyle to secure a timely triumph at Tynecastle.
Genseric Kusunga's first goal of the season had given the visitors a first-half lead before Olly Lee's fortuitous leveller.
Dundee's victory sees them leapfrog St Mirren into 11th and revitalise their survival bid, while Hearts, who visibly missed the influence and quality of the suspended Steven Naismith, slipped to sixth spot.
The visitors were first to threaten when Nelson surged forward and unleashed a ferocious 25-yard drive that forced a fine save from Doyle.
Doyle's opposite number, Seny Dieng, was called into action midway through the first half when he parried an Arnaud Djoum drive to safety.
Dundee claimed a deserved lead after 24 minutes as the industry and drive of Kusunga paid dividends.
The Angola international robbed David Vanacek before racing forward, playing a slick one-two with Nelson and firing a low finish beyond Doyle from eight yards.
Vanacek, clearly well short of match fitness following his move from FK Teplice and on a booking, was hauled off by Hearts boss Craig Levein after just 33 minutes, with Steven MacLean entering the fray.
However, the home side's leveller can be attributed to luck rather than a tactical masterstroke as an inswinging free-kick from Lee took a wicked deflection off Jesse Curran and looped agonisingly over Dieng and into the far corner.
Dieng was forced into sharp stops to deny Callumn Morrison and Christophe Berra as Hearts sought to complete the turnaround after the break, while home fans were buoyed by John Souttar entering the fray for his first outing since suffering a hip injury last October.
However, it was Dundee who would regain the lead when Hearts defender Conor Shaughnessy lost his footing attempting to sweep up a hopeful ball up the flank, allowing Craig Curran to scamper free and produce a perfect cutback for Nelson, whose finish from 16 yards was unerring.
Despite Hearts throwing bodies forward in search of a late equaliser, Dundee showed admirable resilience and organisation to hold on for a precious three points, with a last-gasp volley wide from Aidan Keena the closest the hosts would come.
