Robbie Neilson enthused over his young Hearts defence after they kept a clean sheet to secure their fourth successive league win against Dundee at Dens Park.
Hearts defended stoutly as Dundee piled on the pressure to level after Jamie Walker's winner in the 53rd minute.
"I was really pleased with the back four," explained head coach Neilson.
"Liam Smith, 19, (Jordan) McGhee, 19, (John) Souttar, 19, and (Alim) Ozturk, 22, so to keep a clean sheet against such a good team was very pleasing."
The result leaves Hearts closing in on a European spot, having opened up a 17-point gap over fourth-placed Ross County.
"It's looking good but it's still not secured," Neilson told BBC Scotland.
"We would like to try and do it as soon as possible but it's not something we are talking about. We next have St Johnstone and if we win that then that takes us another step."
Dundee boss Paul Hartley was left scratching his head at how his players were unable to score after creating numerous chances in the game.
"We had some fantastic opportunities and we just didn't take our chances," he lamented.
"Hearts get a golden opportunity and they take it."
Rory Loy missed the chance of the game late on when clean through on goal but was denied by Neil Alexander, who kept a fourth straight clean sheet for the Tynecastle side.
"I think he (Loy) maybe has to go round the goalkeeper and show that little bit of composure," Hartley added.
"It's a good move and I think it's going to be a goal but you need to take your chances or you get punished."
Defeat leaves Dundee in seventh place - two points behind Motherwell, three behind St Johnstone and Ross County - with four games to go before the split, but with a top-six finish still within their grasp.
"We have got four games and we have got to get as many points as we can," Hartley added.
"We have just said to the group, 'Do you want to be in the top half or the bottom half?' It's up to us to try and achieve that."