Zdenek Zlamal's shoot-out save from Nicky Clark proved decisive

Hearts took a significant step towards the Scottish League Cup last 16 after beating Dundee United in a shootout after the sides drew 1-1 at Tynecastle.

Craig Levein's side were flawless from the spot, with former United defender John Souttar scoring the winning kick after Nicky Clark's opening penalty was saved by Zdenek Zlamal.

Marquee signing Lawrence Shankland had put United in front early on, before Andy Irving volleyed Hearts level. The 19-year-old was then sent off late on for a deliberate handball.

But his Hearts team-mates went on to claim two points to top the group, while United have to settle for one.

Both now face group games with lower league sides Cowdenbeath, Stenhousemuir and East Fife, with only the winners of the section guaranteed a place in the knockout stages.

Summer additions help set tempo

Both sides finished last season with crushing disappointment. Hearts were eventually beaten by Celtic in the Scottish Cup final having led past the hour mark, and United were bettered on penalties by St Mirren in the Premiership play-off final.

Perhaps feeling the need to shake off their angst, both started at a frenetic pace, helped by the freshness of summer additions. Rarely has there been such focus on a signing made by a second-tier team, but there were more than a few raised eyebrows when Shankland - having scored 34 goals in all competitions at Ayr United last term - stayed in the Championship by signing for United.

As many as 15 clubs across Europe were said to be chasing the 23-year-old, and his opener demonstrated exactly why. He possesses neither searing pace, nor brute strength or stunning technical ability. But his knack of appearing in the right place at the right time is uncanny.

His stooping header for the opener, peeling away from Christophe Berra, was practically his first touch and displayed his instinctive qualities perfectly. Kudos too for Sam Stanton, whose weaving run and cross teed up his team-mate superbly.

Lawrence Shankland scored a debut goal for Dundee United after his move from Ayr United

Hearts own signings in attack were also impressing. Levein was clear that Jamie Walker has not yet reached peak fitness since his Tynecastle return from Wigan, but nevertheless his clever flick put Conor Washington into the box, only for the Northern Ireland international's drive to flash past a post. Walker himself then scampered through but Benjamin Siegrist stood tall to deny him, and Hearts, an equaliser.

In the end it was 19-year-old academy player and former Tynecastle season-ticket holder Irving who deservedly hauled Hearts level just before the break with a calm, deliberate swipe of his left boot. His volley from the edge of the box snuck into the bottom corner after United made a hash of clearing a free-kick, to leave the game finely poised for the second half.

No doubt with the aim of wrestling some control of the midfield, United head coach Robbie Neilson brought on Calum Butcher and pushed Jamie Robson to left-back, with Adrian Sporle coming off.

It made little impact, even if Stanton went close with a lunging volley 45 seconds into the half. Uche Ikpeazu failed to connect with a header from six yards, then Walker smashed into the side netting as the hosts continued to dictate proceedings. Their wide players, Jake Mulraney and Walker were impressing and Washington too found joy when peeling out to the flanks.

The trio continued to create chances but, as was Hearts' struggle for large parts of last season, goals were not forthcoming. Their wastefulness should have been punished too. A rare foray forward by United ended with Clark with the ball at his feet, six yards out, with goalkeeper Zlamal splayed helplessly on the turf. But the striker inexplicably failed to hit the target.

The fading visitors were then handed a lifeline after Irving tripped while haring after the ball to stop a counter attack, and dived to smother it with his hands to prevent Clark racing through. It resulted in a red card for the youngster, which felt a little harsh given some of the meaty challenges that went unpunished throughout, particularly from United duo Rachid Bouhenna and Mark Connolly.

The sending-off coaxed some life out of the visitors, but McMullan's tired drive past an upright was the final chance and the game petered out as the shoot-out loomed.

United's penalty woes are now well documented. They failed to score a single spot-kick against St Mirren in the play-off final and had lost a further two shootouts in cup competitions last term.

This time, it was only Clark who failed to find the net, Zlamal parrying his weak effort, but Hearts were ruthless. Every one of their penalties were confidently dispatched and their reward is a firm advantage in the race for the only automatic spot in the last 16.

'We could have made it more comfortable' - reaction

Hearts manager Craig Levein: "I was quite pleased with the game. Some of our players were still a bit rusty, but United only had one chance in the first half which they scored. Andy Irving was really unlucky, he's very unfortunate to slip and fall on top of the ball.

"We had a lot of control, a lot of good play and chances. My one main criticism is we weren't ruthless enough in front of goal, or we could've made the night quite comfortable."

Dundee United head coach Robbie Neilson: "I was delighted with the performance and delighted to have scored a penalty. It's been a while, given the previous issues we've had.

"I thought the performance was excellent against a consistent top-six team. We limited their chances, created a few of our own, they put us under pressure but we stood tall."

'United will fancy themselves for the title' - analysis

Former Dundee manager Neil McCann on Sportsound

United were well set up, well organised. Out of possession they got into a solid shape, then tried to expose Hearts on the break. You can see United wanted to play out from the back. It's okay doing that in friendlies, but when the heat's on you need to see how brave the players are, and they need to work on that.

But if Shankland can hit the net like he did with Ayr United, they'll fancy themselves to go up automatically, let alone in the play-offs.

Former Hearts and Dundee United midfielder Allan Preston on Sportsound

Washington got a good 90 minutes under his belt, and Walker got a good 80. Can Sean Clare play in the middle? I don't think he can. Hearts still need a natural goalscorer though, I don't think they have one.