Derek McInnes was proud but frustrated after Aberdeen's Europa League hopes ended with a narrow defeat to Sporting in Lisbon.
Tiago Tomas' early goal edged it for a Sporting team missing nine players because of the Covid-19 outbreak.
Aberdeen struggled to trouble the hosts as the Scottish side faltered at the third round qualifying stage for the sixth time in seven years.
"You can't ignore the quality of the opposition," said McInnes.
"The Covid situation didn't really come into it because that was their strongest team bar maybe one player. They're a team with designs on winning the tournament and we went toe to toe with them.
"I was very proud of the players' efforts. My team was excellent and I'm just disappointed they haven't got anything to show for it."
Sporting host LASK in next week's play-off.
This was a step into the unknown for an Aberdeen side beginning life without Scott McKenna following his move to Nottingham Forest.
A raft of Covid-19 casualties added a touch of mystique to the challenge in Portugal, the only certainty being those who were brought in from the cold were unlikely to be mugs.
And so it proved, with the hosts wrenching open the Aberdeen defence after just seven minutes. Luciano Vietto collected the ball after some dithering and turned for goal.
One drop of the shoulder and a shuttled ball out to his right caught the defence - Andrew Considine in particular - napping. Tomas was clinical in steering the ball past Joe Lewis.
To their credit, Aberdeen rallied. McInnes' men showed bravery on the ball, but struggled to craft any real chances.
The closest they came was a deep Dylan McGeouch cross that Antonio Adam tipped over easily.
In the second half, Jonny Hayes was afforded space down the left, but the former Celtic man blazed over when he should have done better.
In truth, a mixture of poor finishing and instinctive goalkeeping kept the tie alive at the other end.
A scramble in the box was defused by Lewis' sprawling save to halt Boges Cabral scrambling in a second, while Tomas somehow steered a free header wide with the goal gaping.
Man of the match - Jonny Hayes
What did we learn?
Aberdeen lacked a cutting edge in attack and may be left with a feeling of what might have been. Several times they got into good positions against a classy outfit, but couldn't muster anything to trouble them.
Matters could have been different if the injured Sam Cosgrove was in their ranks.
However, McInnes can be content with the performance in trying circumstances. Regardless of the fact Sporting were without several players and their coach, this was never going to be easy.
Add in that Aberdeen were coming off of a 3-0 hiding to Motherwell and without McKenna, and McInnes' men deserve credit for being competitive.
Aberdeen are back on domestic duty with a trip to Dingwall to face Ross County (15:00 GMT) on Sunday.
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