Motherwell stunned Celtic 2-1 at Fir Park to go second in the Scottish Premier League table, while Inverness could only manage a goalless draw with Dundee United.
James McFadden celebrated his first Motherwell start for 10 years by helping Stuart McCall's men to a 2-1 home victory over the leaders.
Michael Higdon volleyed the winner in the 73rd minute as Motherwell beat Celtic for the first time in exactly two years.
Chris Humphrey had opened the scoring prior to the break, before Georgios Samaras headed an equaliser for the visitors.
McFadden had come off the bench twice since re-signing for Motherwell, appearing in consecutive defeats against Dundee United and Ross County which had seen Motherwell slump from second to fourth place.
But his first start since playing for Everton against Wolves on May 6 last year saw them return to second spot.
The 29-year-old helped make his name in a 2-1 victory over Celtic in September 2002 when he scored and tormented Martin O'Neill's side.
His lack of game time meant he was never going to be running at Celtic in the same way on Wednesday night but his skill, improved football brain and willingness to work helped Motherwell boost their hopes of qualifying for Europe.
Inverness dropped a place to third and Dundee United moved up to eighth after a goalless draw at the Tulloch Caledonian Stadium.
Graham Carey scored a stunning goal as St Mirren defeated Hearts 2-0.
The two sides will contest the Scottish Communities League Cup final next month - and Danny Lennon's side struck a psychological blow ahead of that contest with this comfortable victory.
Paul McGowan netted from the penalty spot after three minutes and Carey's impressive looping shot from 25 yards extended their lead on the stroke of half-time at St Mirren Park.
Hibernian twice came from behind to earn a point from their home tussle with Kilmarnock as three of the goals coming in a lively finish.
Sammy Clingan gave Kilmarnock the lead within a minute of the second half starting, with a long-range strike, before Ryan McGivern levelled five minutes from time.
The visitors regained the lead soon after through Jude Winchester, only for Leigh Griffiths to earn Hibs a point with a third goal in as many minutes.
Mark Stewart got new interim Dundee boss John Brown off the hook in his first game in charge as his late goal earned the SPL's bottom-placed team a 2-2 home draw against St Johnstone.
Ten-man Dundee looked set for their 20th defeat of the league campaign after losing Declan Gallacher to a red card for his last-man tug on Steven MacLean.
But former Falkirk man Stewart popped up with a last-minute leveller to keep Dundee 15 points adrift of safety.
MacLean headed the Perth side ahead 35 minutes in, but John Baird cancelled that out with his own header just before the break.
Saints struck again through skipper Dave Mackay's free-kick after 68 minutes as he made sure it was a double punishment for the hosts following Gallacher's dismissal.
However Stewart netted at the end to secure a point.
