Sheffield Wednesday snatched the bragging rights back off city rivals Sheffield United as they earned a 2-0 derby win thanks to goals from Akpo Sodje and Marcus Tudgay.
Sodje struck in the 25th minute and, after the Owls had defended as if their lives depended on it in the second half, Tudgay lashed home a decisive second with 15 minutes remaining.
The win was sweet for most of the 30,486 Hillsborough crowd after the Blades had won the last three Steel City encounters.
Wednesday turned in an impressive first-half display and were well worth their half-time lead.
United poured forward after the restart but Brian Laws' side showed admirable resilience and went on to kill the game.
The Owls edged away from the bottom three with only their second league win in nine matches, while the Blades slipped to another costly defeat to leave a belated play-off challenge foundering.
The 120th Steel City derby went ahead as scheduled thanks to the protective covering employed by Hillsborough's hardworking grounds staff this week which helped to beat the recent heavy rain.
Ronnie Wallwork made his first start for the Owls, but Francis Jeffers (ankle) failed a late fitness test, while Lee Martin, on loan from Manchester United, made his Blades debut and fellow new signing Ugo Ehiogu was on the substitutes' bench. United midfielder Lee Hendrie was suspended.
United goalkeeper Paddy Kenny had already been forced into a terrific save to deny the outstanding Jermaine Johnson before Sodje side-footed home at the far post in the 25th minute.
Sodje, playing despite a troublesome ankle injury, should have doubled the home side's lead just before the break, but Kenny saved well again to gather the striker's shot from inside the box before thwarting Tudgay's 18-yard effort.
Blades' skipper Gary Speed headed wide early on, but Wednesday were first to threaten in the ninth minute when Tudgay fired over after being played in by Johnson's measured pass.
Kenny then pulled off another fine save to deny the Owls a 17th minute lead.
Johnson cut in from the right and his pile driver arced toward the top corner after deflecting off Matt Kilgallon's outstretched boot, but the acrobatic Kenny tipped the ball over his crossbar.
Kenny though was beaten soon after, with Johnson again at the heart of the Owls' breakthrough.
The quicksilver winger curled over an inch-perfect cross for the unmarked Sodje to tap home at the far post in the 25th minute.
Owls' goalkeeper Lee Grant kept the Owls' noses in front three minutes into the second half when he turned Rob Hulse's shot over the crossbar at full stretch after the ball was half-blocked by Tommy Spurr.
Hulse's header from Martin's corner was then cleared off the goal line by Glenn Whelan as the Blades camped on the edge of the Wednesday penalty area.
Johnson and Tudgay then set up Leon Clarke, a 61st minute replacement for Sodje, at the other end, but the big substitute froze and shot tamely at Kenny.
The home crowd sensed their side had weathered the storm with 20 minutes to go before Tudgay doubled their advantage.
Clarke made amends for his earlier miss by hooking Lee Bullen's throw-in across the six yard box and Tudgay lashed the ball home on the volley in the 75th minute.
Clarke almost made it three for the Owls moments later, but his left-footed shot rolled the wrong side of Kenny's post.
The home faithful began ironic chants of Blades manager Bryan Robson's name as his side struggled to carve out any further openings.
Teams:
Sheff Wed Grant, Bullen, Beevers, Hinds, Spurr, Whelan, O'Brien, Johnson (Small 79), Wallwork, Tudgay, Sodje (Clarke 62).
Subs Not Used: Burton, Wood, Watson.
Goals: Sodje 25, Tudgay 76.
Sheff Utd Kenny, Bromby, Kilgallon, Armstrong, Geary, Carney (Sharp 46), Speed, Montgomery (Gillespie 46), Tonge, Martin, Hulse.
Subs Not Used: Naysmith, Stead, Ehiogu.
Att: 30,486
Ref: Mark Halsey (Lancashire).