Head coach Robbie Neilson praised his side's tenacity after Sam Nicholson's late strike secured Hearts a 4-3 victory over St Johnstone.
"We did it so often last season - winning games in the last 10 minutes - and we've done it again," he said.
"Although we're disappointed to lose three goals, it breeds belief in the team that they will go on and win."
Despite lamenting goals conceded, Saints' Tommy Wright was "really pleased with some stuff going forward".
A slip from Brad McKay, who joined the Perth club from Hearts this summer, allowed Juanma to open the scoring for the home side after only three minutes.
"It was a bit of indecision, an unfortunate mistake, but he recovered well," Wright told BBC Scotland.
"Obviously we had a terrible start to the game, but I thought we played extremely well throughout the whole game
"But what's killed us is the poor goals we've given away and you can't do that.
"We did brilliantly to come back to 3-3 and gave away a soft goal again and let them back into the game far too easily."
Wright was pleased at the way his side had harried Hearts high up the park, preventing them building from the back and forcing them to play the ball long out of defence.
Neilson admitted that Hearts, who led 3-1 before Saints fought back to level, had not been at their best.
"It was a really nerve wracking game for us," he said.
"We wanted to get three points, we managed to do it, but the manner in which we did it wasn't what we were looking for.
"We pride ourselves in being defensively strong, but fatigue played a big part in this because we had four or five boys who have hardly any pre-season.
"We patched them up to try to get them out for this game - Rossi, Augustyn, Juanma, Prince Buaben as well, but I thought they were all fantastic.
"They really worked hard and you could see in the last 30 minutes they were out on their feet, but they kept their character and kept going, winning their headers, winning their tackles, and got us the three points."
Hearts were returning to the top flight after a season in the Championship and the victory gave Neilson hope that they can compete in the top flight.
"I have a lot of belief in the players," he added. "They believe in each other.
"The atmosphere was phenomenal. The fans backed us to the hilt the whole road last season and they have started the same way.
"We can only repay them by giving 100% and I think the players did that."