Robbie Neilson hailed Finlay Pollock's impact after the teenager netted his first Hearts goal in a 2-0 victory at Stirling.
The 17-year-old came off the bench to net Hearts' second goal and seal Premier Sports Cup progress.
The midfielder has been catapulted into the first-team reckoning this summer and has grasped his chance.
"I'm delighted for him," Neilson said. "I thought he did really well when he came on. I considered starting him but we just felt he had played the last few games and it's important he is fresh when he comes in.
"It's great for him. He makes some great runs forward, he is positive and has great energy, and he brings that to the team, which is important.
"I am pleased for him but he is still young and he has still got a lot of improvement to come.
"He is a box-to-box midfielder, he will get back and forward. For us at the moment it's just getting him game time and getting used to the physicality of being about the first team but he is certainly handling it well."
Liam Boyce netted after a quiet first half-hour as Hearts secured top spot in Group A with the help of Cove Rangers' 3-1 win over Inverness.
"That's us qualified for the knockout stages, which is the most important thing," Neilson said.
"I thought it was fits and starts in the game but overall it's another three points and clean sheet."
