Ivan Sproule's second-half header brought Ross County a first win in almost 15 years over visitors Dundee United, who had Barry Douglas sent off.
Iain Vigurs and Steffen Wohlfarth had early chances for County while Jon Daly's header was close to giving United a half-time lead.
Sproule netted from Vigurs' cross and Douglas's red card for a foul on the goalscorer shortly after seemed harsh.
The crossbar denied Richard Brittain from doubling County's lead.
Sproule being in the right place at the right time to register his sixth goal for Ross County since he joined in January means his side are propelled up to fourth place in the Scottish Premier League.
With eyes on European football next season, they are now breathing down the necks of northern neighbours Inverness CT with a Highland derby still to play.
It was also the Northern Irishman's foot which was caught late by United's left-back Douglas in a second-half challenge that referee Kevin Clancy deemed worthy of a red card, when most at Victoria Park expected to see yellow.
The Tayside outfit remain in sixth position and this was their first defeat by County since two goals from their current manager Derek Adams put them to the sword in a League Cup tie in 1998.
On a poor surface, Vigurs had the hosts' early attempts on goal; firstly testing United goalkeeper Radoslaw Cierzniak with a low left-footed effort after Willo Flood's mis-control, then slicing wide from Sproule's centre.
Flood, taking longer to get up to speed than visiting manager Jackie McNamara would prefer, was caught in possession by County midfielder Paul Lawson, who in turn unleashed a searching pass through the middle for Sproule.
Cierzniak, though, rushed out to clear well.
Sproule capitalised on Flood's third error in quick succession to send a sweeping ball to Wohlfarth, but the Dingwall side's bustling German striker had his shot from 10 yards blocked by United defender Brian McLean.
Working out how to cope with Tangerines front-man Daly is a work in progress for defences around the country and his header from Douglas's free-kick would have found the bottom corner had it not been for Michael Fraser's diving save.
Lawson had already shown an aptitude for long-range passing and after the break he did so again, to great effect.
This time he found Vigurs on the left-hand side of United's box, who stole a yard on Sean Dillon in making for the bye-line and dinked a perfect cross to the back post for Sproule to nod into the net under pressure from Douglas.
The former Hibs striker had an eventful night, recovering from the foul that resulted in Douglas's dismissal to cut back the ball for another Vigurs half-chance.
Captain Brittain, top scorer for club so far in 2012-13, has been instrumental in a successful County side and his 25-yard strike was nearly his 11th goal of the season, but it thumped the crossbar.