THEY are staying up.

Retaining their place in the SPFL Premiership has never looked as if it was mission impossible for Partick Thistle and after last night it is now mission accomplished.

While Hibernian and Kilmarnock prepare to battle it out to avoid finishing in the relegation play-off slot this season when they meet on Saturday afternoon, Alan Archibald's side can look forward to their match with Ross County in the knowledge that their job is done.

After a nine-year absence from Scotland's top flight, Thistle have guaranteed themselves another 12 months at this level, a 4-2 win over Hearts at Tynecastle last night their most important triumph of the campaign.

It is a deserved achievement for the Firhill side and manager Archibald who, one year after guiding his side to the First Division title, has now ensured that Thistle will be no one-season wonders. They have done it with a style and philosophy that has won them many admirers and, with 38 points now collected, they could yet finish a remarkable seventh.

"It is hard to put into words, it is massive for everyone at the club," Archibald said. "I have been through relegations and it is horrible. It affects everyone at the club and everything you do from having your lunch to the secretarial staff, it affects the whole shooting match.

"It is massive and I think the fans deserve it here. I said to the boys, there is no reason why we can't be like a St Mirren or a St Johnstone, they are the benchmark for us, they have came up and stayed up."

With their County match still to come this weekend, it was not exactly win or bust for Thistle last night but they were determined to avoid what would be a nerve-shredding afternoon at Firhill. The opening goal would have eased Thistle nerves and put them on the right track but it was instead Gary Locke's side who got off to the perfect start, Callum Paterson rifling home from the edge of the area.

Things almost, and should have, got worse for Thistle before they got better but Billy King blazed his effort over with only Paul Gallacher to beat.

It was a major let off for Archibald's side and it did not take long for them to cash in. After Higginbotham again had a pop from distance, the visitors' playmaker would have a hand in Thistle's leveller, a neat flick setting Lyle Taylor on his way to goal and the striker made no mistake as he slipped the ball under Mark Ridgers.

It should have been the springboard the visitors needed to go on and clinch the much-needed win but it was Hearts who would take the third goal of an entertaining first half. It was another poor goal to concede from Thistle's point of view, Danny Wilson able to rise highest at the back post and head home a Kevin McHattie free-kick.

With Kilmarnock ahead at half-time, the away dressing room would not have been a happy place as Archibald addressed his troops. His words of encouragement certainly did the trick, though, as Thistle netted three times without reply to clinch the crucial three points.

Gary Fraser got the ball rolling with a superb shot from 25 yards that found the top corner of Ridgers' net to put Thistle level and, with more than half an hour to complete the job they set out to do at the start of the evening, the finishing line was in sight.

Having conceded from a set piece earlier in the match, Thistle scored from one themselves to put themselves in control of the match and edging ever closer to safety, Lee Mair was the hero this time as he nodded in at the back post. The celebrations were tinged with a degree of trepidation, especially given the way in which Heart have battled away in recent weeks, but when Thistle got their fourth of the night, players, staff and fans alike could begin to believe.

Ridgers could only parry a low shot from Taylor and Higginbotham was quickest to the rebound as he fired through the keeper's legs and wheeled away to get the party started.

Archibald can now plan for next season, but his opposite number Locke will have to wait to have his future confirmed by new owner Ann Budge. There was to be no fifth successive win for Hearts as they took their final bow as a Premiership side, but they have shown enough in recent weeks to ensure they head for the Championship undaunted, even with the spectre of Rangers lying in wait.

"The players deserve enormous credit, they have been fantastic," Locke said. "Tonight, we looked a bit tired towards the end, which is understandable with a young side.

"The players have applied themselves brilliantly over the last couple of months."