The fabulous form that saw them beat Rangers and Motherwell deserted Dundee at Dens as they slipped out of the top six.
It was their opponents, a well-organised and energetic Partick Thistle side, that took their place in the Premiership’s upper half.
This was a meeting of two of the division’s in-form sides but it was Alan Archibald’s men who kept the momentum going after their successive victories over St Johnstone, Hamilton and Hearts.
Dundee’s last home defeat in the league had been at the hands of Thistle back on October 26 and the Jags repeated the feat thanks to an own goal from Dark Blues defender Julen Etxabeguren on 29 minutes.
The hosts never recovered from that setback and even six minutes of stoppage time – allocated due to a serious-looking injury to Etxabeguren – didn’t help them and some supporters vented their frustration at full-time.
It wasn’t exactly a shock that the Dens men had gone with the same starting line-up for the third match in a row.
It was a significant show of faith in his men by manager Paul Hartley but an understandable one given those performances against the Light Blues and Steelmen.
The Jags made only one change, with Christie Elliott coming in for Mustapha Dumbuya.
The match was slow in catching fire and the first serious attack was from Thistle on 12 minutes, when Callum Booth’s cutback was fired at goal by Chris Erskine but comfortably saved by keeper Scott Bain.
Dundee were almost gifted a chance on 15 minutes when Partick goalie Tomas Cerny, the victim of a hospital pass from Booth, blasted his attempted clearance off Marcus Haber but the loose ball ricocheted to safety.
Just a minute later, the lively Ryan Edwards steered a shot wide of the Dundee goal.
The game was warming up nicely now and Jags defender Liam Lindsay gave his own side a scare when he sliced Craig Wighton’s cross over his own crossbar.
Dundee were pressing and Kevin Holt watched his cross from the left flank clip the Partick post on 21 minutes before Henrik Ojamaa raced towards the Thistle box but shot weakly wide.
A couple of minutes later it was the Maryhill men who were on the front foot, with Kris Doolan firing just wide after being played in by Erskine.
On 29 minutes, Thistle edged ahead thanks to an own goal by Etxabeguren.
Doolan and home skipper Darren O’Dea raced for the ball inside the Dundee box and the big defender fell to the floor looking as if he had been shoved.
With no whistle sounding, Doolan kept going and cut the ball back at the near post trying to find Edwards.
It struck the unfortunate Spaniard before it reached the Jags player, though, and deflected into the net.
It was a sore one for the home team but, to be honest, the Jags probably deserved it for their more enterprising play.
There was an injury scare for both teams five minutes before the break when O’Dea and Edwards suffered head knocks after challenging for a cross but they both played on after treatment.
The Dark Blues came out for the second half looking to shake off their lethargy and, on 52 minutes, a strike from the edge of the box by James Vincent stung the hands of Thistle keeper Cerny.
Ojamaa and Haber both had goes at the Thistle goal but Bain had to come to Dundee’s rescue at the other end on the hour when he scooped up the ball after Elliott’s cross from the right had struck Cammy Kerr and headed goalwards.
The home fans were getting restless now and, as if in recognition of that, Dundee made a change on 65 minutes by bringing on Faissal El Bakhtaoui for Ojamaa.
There was real concern for the home team a couple of minutes later when Etxabeguren fell to the floor with what looked like a bad injury. As a hush went around the stadium as the medical staff raced onto the park.
He was carried off on a stretcher and replaced by Kosta Gadzhalov, while Danny Williams also came on for Wighton.
Former Dundee United man Erskine, who had run hismelf into the ground for the Jags, was then replaced by Steven Lawless on 77 minutes.
Thistle kept going forward and they had the ball in the Dundee net a couple of minutes later, only for “scorer” Doolan to be flagged offside as he converted Osman’s cross.
Up at the other end, a period of home pressure ended with O’Dea heading just past the back post from close range following Paul McGowan’s cross.
The Dark Blues pushed hard in stoppage time but the Jags held on to leapfrog their hosts into that much-desired sixth spot.
Attendance: 5,328.
Dundee: Bain, Holt, Vincent, O’Dea, O’Hara, Etxabeguren (Gadzhalov 69), McGowan, Haber, Ojamaa (El Bakhtaoui 65), Kerr, Wighton (Williams 69). Subs not used: Gourlay, Hateley, Ross, Gomis.
Partick Thistle: Cerny, Booth, Lindsay, Osman, Doolan (Azeez 86), Erskine (Lawless 77), Barton, Elliott, Devine, Keown, Edwards. Subs not used: Ridgers, Amoo, Nisbet, McCarthy.
Referee: John Beaton.
