Calderwood is bitterly disappointed after going down 3-0 in Athens

The 3-0 defeat in Athens leaves the Dons at the foot of group B.

"If we play like that then we can forget it. We've let ourselves and our supporters down," said Calderwood.

"We're certainly not giving up. We've got two home games and Aberdeen fans on these special nights create a cauldron and we'll need that."

Interview: Aberdeen midfielder Barry Nicholson

Interview: Aberdeen manager Jimmy Calderwood

Calderwood lamented his team's defending as they lost two goals from dead ball situations.

The home side took the lead when captain Giannis Goumas headed home Andreas Ivanschitz's free-kick after 10 minutes.

Second-half goals by Dimitris Papadopoulos, and then Dimitrios Salpigidis from another Ivanschitz free-kick, put the game beyond Aberdeen's reach.

"I'm very disappointed. That wasn't us tonight," said Calderwood.

"The annoying thing for me is that they didn't have to work too hard to get the victory as we've had two soft goals against us."

"We keep telling them not to give free-kicks away in these areas because these lads are fantastic at them."

"I don't think it was ever three-nil. But you get punished at this level for mistakes."

The match was the Dons' first venture into the group stage of the competition, and their return to Europe after a five-season hiatus.

"We've worked so hard to get here through the years, and it's great to be here, but you still want to do something in it," Calderwood added.

Midfielder Barry Nicholson agrees with his manager about the defending at free-kicks, but is also rueing his side's missed chances.

MY SPORT: DEBATE What now for the Dons chances of progressing?

"We were disappointed to lose the first goal from the set-piece," he said.

Aberdeen's best chance fell to Chris Clark who he fired just over the bar from inside the penalty box.

"It's a tough group, but if we had stuck our chances away it could have turned out different," Nicholson added.

"There's a few young boys in the squad so it's a different environment for them, but it's a great learing curve for us and hopefully we can learn from this."

Aberdeen next host Lokomotiv Moscow at Pittodrie on 8 November.