Scottish Cup finalists Hearts turned the game with goals from Liam Boyce and Josh Ginnelly either side of the break. And although Ryan Edwards levelled, substitute Simms lashed in the winner with seven minutes to go.

Hearts, who have already secured a Europa League play-off place, extend their unbeaten run in all competitions to nine.

And United remain a point above Motherwell and Ross County, who also lost this weekend, with the trio battling to claim two places in the qualifying rounds of the Conference League.

Tam Courts' side started in the manner of a team with a prize at stake, Nicky Clark heading wide at an early corner - and the forward was involved again as United took the lead.

Clark played a one-two with Tony Watt and, although Craig Gordon saved his shot, possession was recycled for Levitt, who showed a delicate touch to evade two defenders and jab the ball into the left corner.

Hearts - who had scored nine times in three meetings with United prior to this one - responded with a shot over the bar by Aaron McEneff before the midfielder made way injured for Ben Woodburn.

Boyce was next to threaten for the visitors after latching on to Barrie McKay's superb pass, Benjamin Siegrist making a fine save to deny him.

Two Ginnelly efforts in quick succession had to be dealt with by United defenders and a Boyce header was blocked by Ross Graham as the visitors kept the pressure on.

And their reward came when Nathaniel Atkinson's driven cross was pushed out by Siegrist but only on to the chest of Boyce, who bundled it into the net.

Hearts continued where they left off after the break and Ginnelly smacked a shot off the outside of the right post before testing Siegrist with a low drive.

And the winger got his goal after chasing Alex Cochrane's long ball and nipping past the onrushing goalkeeper to shoot into the empty net.

United were not done, though. Substitute Kieran Freeman drew a save from Gordon and the leveller soon came from the same right-hand side of the pitch, Edwards thundering a shot into the opposite corner from 25 yards after some deft footwork.

However, there would be no precious win for the hosts, with Simms timing his diagonal run perfectly to receive McKay's pass and finish first time past Siegrist and claim a third win in four meetings of these sides this term.

Man of the match - Josh Ginnelly

Winger Josh Ginnelly was industrious in his 72 minutes and got a deserved goal

What did we learn?

United's saving grace this weekend has been their nearest rivals also losing, but both Motherwell and County have now played one of their post-split games against the Old Firm.

Going forward, they looked more than capable against Hearts but were caught out by direct balls at crucial times.

Hearts arrived at Tannadice with injury problems and McEneff's early withdrawal added to the absence of Craig Halkett, John Souttar, Stephen Kingsley and Andy Halliday.

But the strength of the squad showed, with Ginnelly in particular staking his claim for a cup final place and on-loan Everton forward Simms again impressing.

What did they say?

Dundee United head coach Tam Courts: "We are scoring early on in games. The disappointing thing for me is that we're not adding to that tally.

"The [Hearts] goals were really soft goals. All in all, a really frustrating day for us. We're not under any negative pressure, we can play with a bravery and a fearlessness. That's the football that will be rewarded."

Heart of Midlothian manager Robbie Neilson: "We didn't start well. To Dundee United's credit, they put us under a lot of pressure. After the first 15 minutes, we started to create chances.

"Delighted for Josh, he's been out the team for a while. He's been working hard. Ellis is on fine form and we just have to enjoy him as much as we can right now. If we can keep Ellis next season, great - but it's totally out of our control."

What's next?

United are at home again on Saturday against Motherwell, while Hearts host County (both 15:00 BST).