Arsenal manager Arsene Wenger admits it is 'amazing' to still see Henrik Larsson playing top-level football.
The 35-year-old Swede looked set to make the move back to his homeland with Helsingborg the last of a glittering career when he left Barcelona in the summer.
However, the former Celtic striker threw himself back into the thick of the action when he opted for a shock loan move to Manchester United.
Wenger joked that Larsson's match-turning performance off the substitutes' bench for Barca in last season's Champions League final still gives him 'nightmares'. The veteran helped his team recover from a goal down to win the match in Paris 2-1.
However, the Gunners boss has nothing but admiration for the veteran forward as he prepares for Sunday's clash with the Premiership leaders at the Emirates Stadium.
Wenger said: 'I like first of all his intelligence and I like his team attitude. That is basically what I admire with Larsson.
'He said he was stopping, and I was not aware he was available.
'I thought frankly his time was over at 35. It is amazing.'
United are some 15 points ahead of Arsenal and could effectively end any hopes of a late surge from Wenger's men with victory tomorrow.
The Gunners boss believes his men are more than up for the challenge.
He said: 'There is a mixture with tension and enjoyment - people are happy to play a big game, and it also brings a part of stress.
'That is why experience is important - not to play the game before the game.'
Wenger knows what a boost victory over the leaders would have for his emerging squad.
The Arsenal boss said: 'I can understand that even if we win people still think we have no chance, but we see things differently.
'I believe that for a team which is young like my team, it is important that they get the belief that they can win the big games - game after game. They win one, they win two, they win three and suddenly that can transform a team.
'Then you say 'nobody can stop us' and they can strengthen that belief.
'They have done it already - but they can strengthen that belief by beating Manchester United.
'We want to reduce the gap on Manchester United as quickly as possible and we want to continue our run because we are in good form.
'We are involved in nearly every competition, even the championship, and you never know.'
Wenger maintains his emerging squad have the 'ingredients and potential' to consistently challenge for top honours.
He said: 'At the moment we are not (the best) because we lost at places like Sheffield United, Bolton and Manchester City - even though they are games we could and should have won. But we are getting there.'