Saints were involved in the tournament's most dramatic final last season when they established a 22-6 interval lead against Leinster only to crumble through exhaustion in the second half.
Fatigue from competing on two fronts caught up with them in the most spectacular way at the Millennium Stadium and the club have been busy signing players to prevent a similar scenario from unfolding.
Ryan Lamb, Tom May and George Pistil are among a string of new arrivals and Hartley, speaking at today's Heineken Cup launch, believes Saints are now better placed to go all the way.
But the England hooker accepts they still squandered a glorious opportunity to claim a second European crown, no matter how drained they may have been.
"It's not the pain that motivates you. You're in the competition because you want to win it, but that's not easy," he said.
"Our run to the final last year was great and was difficult, but you have to play for 80 minutes and we didn't do that.
"We were tired because we'd had the semi-final against Leicester the week before, but we were still well in front and we threw that away.
"We threw away the Heineken Cup and that hurts. Afterwards there was this feeling of exhaustion and disappointment.
"But look at Munster. They lost two finals before they won one. We're a young squad and have our best years ahead of us.
"We haven't lost anyone, instead we've added more depth which is probably what we needed on last year.
"We were fighting on all fronts, playing Premiership games to qualify for the top four alongside a Heineken Cup run.
"It's mentally tiring getting yourself up for games every weekend at that stage of the competition.
"If you find you've got competition for places, you can swap people in and out and that's good for the club."
Hartley is one of five England players who have returned from a hugely-disappointing World Cup and the Saints captain admits he has not found the readjustment to club rugby easy.
"We were disappointed to get knocked out early. The best way for me to get over that is to play for Saints," he said.
"I've played three games. I'm moving on and the Heineken Cup will help with that.
"I'd be lying if I said it's easy coming back after a World Cup. I was Eden Park one week and Bridgend the following week.
"I wouldn't say it was a comedown, it was just different. I've found my feet again."
Northampton director of rugby Jim Mallinder admits the 33-22 loss to Leinster continues to cause sleepless nights.
"Something like that doesn't stay in the memory for weeks, more like for years. That was the toughest defeat I've had to take," he said.
"It was the opportunity of a lifetime and you'll never be involved in too many Heineken Cup finals. We lost one and that will never go away.
"But the good thing about it is that you always have a chance to go again and that's the way we must look at it."
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