Watford goalkeeper Heurelho Gomes has described Arsenal as "a small team" after their FA Cup exit on Sunday.
The holders were beaten 2-1 by Quique Sanchez Flores' side at Emirates Stadium, prompting further criticism of manager Arsene Wenger after recent protests from supporters.
Wenger dismissed the scrutiny over his position as "a farce" but, ahead of their Champions League trip to Barcelona this week, former Tottenham man Gomes has questioned their mentality when it comes to key matches.
"It is the best time to play Arsenal and we came to the match very confident," he told ESPN Brasil.
"When you see Arsenal playing against big teams, they look like a small team. They don't look like winning a title soon.
"We knew once we had the ball we'd be able to pass it around since Arsenal gives you too much space. They are not strong defensively."
Arsenal, who have won just one of their last seven games in all competitions, must overcome a 2-0 deficit from the first leg against Barcelona if they are to reach the quarter-finals.