THE Ange Postecoglou mantra famously drilled into his Celtic players is that they never stop, and the win over Hearts provided a perfect example of just why that approach is so key to his team’s success.

At Celtic Park, even the ballboys and ballgirls have been well drilled at getting the ball back into the hands of a Celtic player as quickly as possible when it leaves the field of play. At Tynecastle on Saturday though, not so much.

A Hearts supporter though played an unwitting part in Celtic’s crucial second goal, heading a Kyle Rowles clearance back towards the pitch – as fans are prone to doing – and straight into the arms of opposition right-back Alastair Johnston.

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With Hearts sleeping, he immediately threw it to Jota, who returned it for the Canadian to centre for Kyogo. The forward then produced an impudent backheel to effectively finish the match as a contest on the stroke of half-time with the Hearts defence flat-footed.

“I never noticed that at the time,” said Celtic captain Callum McGregor. “I’ll thank him as well!”

It was that trademark relentlessness though that was to thank for what in the end was a comfortable victory over a Hearts team that were decimated by injuries and lacking in inspiration.

Celtic started like a train, going close in the opening seconds through Reo Hatate, and taking the lead soon after through a brilliantly controlled Aaron Mooy finish.

“We spoke about that,” McGregor said. “Cup ties here are always difficult. Any time you come here, even in the league, the crowd like to get involved in the game.

“We spoke about that beforehand. We wanted to try and take ownership of the game as early as possible.

“Sometimes that doesn’t always happen it right from early on, the first couple of minutes, we really took the game by the scruff of the neck, got control of it, got a goal and we continued to probe right up until half-time when we got the second.”

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Their defensive rock, Cameron Carter-Vickers, popped up at the other end to nod home a Matt O’Riley free-kick late on to give the scoreline an accurate reflection of Celtic’s domination.

“We just have to try and deal with that [the ball coming back in slowly]”, he said.

“We speak about trying to have the ball in play as much as we’re possibly can. The second goal is a good example of that.

“A minute or so before half-time, the ball goes out, they maybe go to sleep a little bit, we’re sharp, we get the ball back in, and we score the second goal which ultimately gives us comfort in the game.

“We always pride ourselves on small details in the game. If they are trying to stop us, we just try and get the ball back in play as quickly as possible.”

Another facet of this Celtic side that is often overlooked is their physical resilience. At times on Saturday, Hearts attempted to mix it a little to upset their opponent’s rhythm, with Kio in particular putting himself about in the middle of the park.

When the Hearts man flattened Kyogo and then immediately tripped Hatate, it was no surprise to see McGregor respond soon after by laying out Jorge Grant when the opportunity was presented to him, sending a message that his team would not be intimidated.

“It’s a cup tie, cup football and it’s a competitive sport,” he said.

“So, of course there are going to be moments in the game where you have to duel and be strong.

“We pride ourselves on that as well. We don’t just want to be a pretty football team and not be strong when it matters.

“I think as a group we’ve shown that in the moments when we’ve had to. Obviously when you win those it gives you a little bit more confidence.

“When you start winning second balls, it takes the edge away from the opponent.

“We do pride ourselves on that as well.”

From a Hearts point of view, the natural and understandable impulse after the match was to look forward rather than dwell too much on a disappointing afternoon, and goalkeeper Zander Clark certainly has plenty to look forward to on a personal level over the next couple of weeks.

The keeper, who has impressed since replacing the stricken Craig Gordon, couldn’t be faulted for his own efforts at the weekend, pulling off two big saves from Hatate in the first half and another to deny Jota after the interval.

He looks certain to be included in Steve Clarke’s Scotland squad when it is named tomorrow for the matches against Cyprus and Spain at the end of the month, and is fancied to even claim the gloves for those games despite the inclusion of Norwich City goalkeeper Angus Gunn, who has finally declared for Scotland.

"It's a clean slate for everybody going in, whoever that may be,” Clark said.

“If it's myself, Angus, Liam Kelly, Jon McLaughlin - it's an opportunity. There is going to be a new face in between the sticks.

“It's been a long time since there's been a fresh face in there. It's up to us to train well and show the manager that we're capable of doing the job.

"Craigy, Greegsy (Allan McGregor) and big Marsh (David Marshall) have played nearly every game for Scotland for the last 25 years or something, so it's going to be a clean slate. If you're in the squad, it's an opportunity to show the manager you are ready to step in.

"I believe in myself. I've played in high-profile games. That would be a massive moment, but I need to make sure I'm in the squad first before I start talking about that.”