Ten-man Hearts succumbed to defeat at Firhill as Partick Thistle continued their impressive recent form.
Esmael Goncalves was sent off for the visitors in the second half as Kris Doolan and Liam Lindsay struck the decisive goals. Hearts had travelled to Glasgow hoping to recover from a dispiriting midweek Scottish Cup exit against rivals Hibs. Backed by 1349 away fans, they suffered another disappointing defeat against an energetic Thistle side.
Doolan's early goal set the tone for the afternoon and he could have scored another - perhaps two - before the break. Hearts didn't create much during the first 45 minutes and, after Goncalves 60th-minute dismissal, struggled due to their numerical disadvantage. Centre-back Lindsay found time to turn and strike the crucial second goal 17 minutes from full-time.
Hearts had been forced to replace Aaron Hughes 45 minutes before kick-off due to a calf problem. Defender Faycal Rherras was elevated to the starting line-up despite not being amongst the original list of visiting substitutes. He started at left-back, with Lennard Sowah shunted inside to centre-back alongside Tasos Avlonitis.
Partick Thistle, with five wins and two draws from their last nine matches, were eager to continue momentum and capitalise on any lingering Hearts despondency from Wednesday night. They moved ahead inside five minutes. Sowah's attempted clearing header was poor and went straight into the air. It fell at the feet of Doolan, who was allowed to turn and slot the ball into the corner of Jack Hamilton's net from six yards.
Once again, Hearts required character. They pushed forward and looked threatening through stand-in captain Jamie Walker and teenager striker Rory Currie, who had been deservedly selected from the start. Thistle's ability to break quickly through their five-man midfield meant the Edinburgh side also had to remain vigilant in defence.
Doolan had the ball in the Hearts net again on 26 minutes, only to be denied by an offside flag. He was then thwarted by an excellent smothering save from Hamilton, who emerged to good effect when the Thistle striker fastened on to a deflected through pass in behind his centre-backs.
It was clear that Hearts were giving their hosts too much space in midfield and in the final third. The defence looked disjointed and midfield required impetus. Thistle, by contrast, were executing manager Alan Archibald's gameplan well, with plenty good passing combinations.
Doolan found himself with a glorious chance to double his team's advantage from Adam Barton's left-sided cross. Unmarked eight yards out, his header was parried by Hamilton. Walker then left the field to be replaced by Sam Nicholson after suffering a head knock. Nicholson assumed the captain's armband for the second half.
French winger Dylan Bikey replaced Currie to make his Hearts debut with the visitors by then in a 4-3-3 formation. However, their task became evermore daunting when they were reduced to ten men. Goncalves received a caution for dissent on 49 minutes and a late tackle on Thistle substitute Christie Elliott earned him a second yellow card, followed by a red, 11 minutes later.
Lindsay secured Thistle's victory with some 17 minutes left. He was given time inside the penalty area to bring down a cross ball and drive it beyond Hamilton. It was a stunning finish for a centre-back - leaving Hearts down and out in Maryhill.
Partick Thistle (3-5-1-1): Cerny; Keown, Devine, Lindsay; Dumbuya, Edwards, Osman, Barton, Booth; Erskine; Doolan.
51: Elliott for Dumbuya
76: Lawless for Erskine
83: Azeez for Doolan
Unused subs: Ridgers, Amoo, Nisbet, McCarthy.
Hearts (4-4-2): Hamilton; Struna, Avlonitis, Sowah, Rherras; Djoum, Tziolis, Nowak, Walker; Currie, Goncalves.
42: Nicholson for Walker
58: Bikey for Currie
80: Choulay for Rherras
Unused subs: Noring, Kitchen, Smith, Martin.
Referee: Nick Walsh.