Arsenal manager Mikel Arteta (AFP)
Arsenal had been on an impressive run as they sought to secure a Champions League place for next season but have lost three out of their past four games.
Southampton, who have taken just one point from their past five league matches, were hammered 6-0 by Chelsea last week.
Arteta believes both sides will be feeling the effects of recent defeats.
"I think you are going to see two teams that are hurting," the Arsenal manager said on Friday.
"We are hurting because of the last two games and we want to perform and win and I am sure after the home defeat that they had they want to do the same."
The Gunners' north London rivals Tottenham currently sit in fourth spot, three points clear of Arteta's side, having played one game more.
The Spaniard said Arsenal's ambition to finish in the top four for the first time since the 2015/16 season, when they finished second, was fuelled more by the club's rich tradition than competition with Tottenham.
"I think it's related to our history, we want to not be fourth but third, second, or first and that's what we have to do and that's always within every supporter and anyone who has any connection with the club," he said.
"So the moment that you see the team doing better and having better aspirations, your tendency is to get excited about it and I think that's the right reaction."
Speaking about the rest of the season, he said: "There's going to be some twists still for sure and the pressure and situation is going to keep changing between now and the end of the season. We have to be focused on us and what we have to do."
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