Dundee fell to their sixth successive league defeat and remain rooted at the foot of the Premiership with a relegation battle looming unless their fortunes improve dramatically.
For Thistle, it was their first win over Dundee in fifteen Premiership attempts and it came courtesy of goals in either half from Ade Azeez and Kris Doolan which was no more than they deserved for their overall efforts to move them above Motherwell into fourth-bottom spot.
Paul Hartley’s side, who haven’t won in the Premiership since their 3-1 opening-day success away to Ross County, are still without a home win at Dens Park this season and last night rarely looked like ending that sorry sequence to leave themselves three points behind second-bottom Motherwell.
This was yet another sucker-punch for the toiling Tayside outfit who now have to negotiate a tricky trip to face Hamilton on Saturday, with Accies bound to be buoyed by their victory over Aberdeen earlier this week.
Seeking a pre-match boost, Hartley, pictured, handed a debut to Canadian international striker Marcus Haber who had signed 48 hours earlier until the end of the season.
The 27-year-old, who had a previous spell in Scotland with St Johnstone, was thrown straight into action in the hope he could apply the killer instinct so visibly lacking in recent weeks.
Haber began up front alongside Craig Wighton while Mark O’Hara, Faissal El Bakhtaoui and Nicky Low all missed out through injury.
For Thistle, defender Liam Lindsay made it despite sustaining a neck injury in their 1-1 draw with Ross County the previous weekend, but Steven Lawless, Tomas Cerny, Stuart Bannigan and Mustapha Dumbuya were all sidelined.
Dundee were aspiring for their first home league victory of the campaign, and their recent record against Thistle at least provided them with some hope.
In fourteen encounters with their Glasgow opponents, the Dark Blues had never lost and knew victory on this occasion would lift them off the foot of the Premiership.
It was a brisk start from both sides and, in nine minutes, Thistle threatened first.
Sean Welsh’s corner is deep but flicked back in to the box only for Azeez to rattle the underside of the crossbar. before the hosts scrambled the ball to safety.
But they didn’t have to wait too much longer to forge a breakthrough, going ahead in simple fashion in 28 minutes.
Abdul Osman’s cross deep into the box was met by Azeez and he dispatched a header back across Scott Bain, the home keeper, to put the visitors in front.
Dundee were all effort with precious little inspiration and Thistle remained the more likely side to increase their lead after the break.
They duly did in 61 minutes, with a helping hand from their opponents.
Bain played the ball out to Kevin Holt on the left, but the Dundee defender hesitated for a split-second and lost possession to Azeez, who wasted no time in crossing for Doolan to usher the ball home into the empty net.
Azeez was involved again in 71 minutes, but this time the Englishman’s effort was blocked by Bain.
Despite falling further behind, Dundee offered little in terms of mounting a comeback and their lack of threat surely the biggest concern to Hartley who now has to lift his players for their visit to New Douglas Park this weekend.