Arsene Wenger's side rarely threatened on the south coast in a game that the relegation-threatened hosts looked more likely to win. Saints proved a much different proposition to the team that Arsenal ruthlessly dispatched of 6-1 in September, taking the lead after 34 minutes through Gaston Ramirez.
The lead lasted seven minutes, though, as Theo Walcott, making his first appearance at St Mary's since leaving in 2006, whipped in a free-kick that Do Prado could only prod into his own goal. It proved the evening's decisive moment as, try as they might, Southampton were unable to find a winner in a second half they dominated.
Arsenal began strongly at St Mary's and Santi Cazorla saw a long-range strike deflect just wide in the fifth minute. Southampton's Artur Boruc was fortunate that his fumble at the resulting corner did not cost his side.
After Maya Yoshida saw penalty claims waved away, Steven Davis almost found Rickie Lambert with a through ball. The striker was offside anyway and Arsenal soon returned to the attack, with Yoshida having to react smartly to block a Lukas Podolski strike.
The opening goal came as Arsenal failed on a number of occasions to clear the ball and, after seeing a shot blocked, Jason Puncheon pulled back for Ramirez to fire home just inside the 18 yard box in the 34th minute.
The lead lasted just seven minutes, though, as Puncheon gave away a free-kick wide on the left. Walcott swung it in and Do Prado directed past his own goalkeeper at the near post. Arsenal thought they had a second before the break as Walcott found a way past Boruc, only for it to be chalked off for offside.
Arsenal goalkeeper Wojciech Szczesny proved his worth in the 56th minute by denying the hosts twice in quick succession, palming a threatening Do Prado effort behind and from the resulting corner reacting quickly to stop Lambert bundling home.
Walcott stung the palms of Boruc on a rare Arsenal move forward, before Ramirez saw a goal ruled out for a foul. Both managers made changes in a bid to find a winner, with Mikel Arteta coming close with a fierce 25-yard strike.
Gervinho hit the side-netting as Arsenal again came close, while Szczesny parried a late Puncheon strike and Yoshida cleared a later cross as the match ended level, propelling Saints out of the drop zone.
Source: PA
Source: PA