Nigel Adkins' second-placed side would have opened up an unassailable eight-point lead over promotion rivals West Ham if they had won on Teeside.
But, despite taking the lead through Billy Sharp's strike just 46 seconds into the match, the Saints allowed Middlesbrough to take the points thanks to Nicky Bailey's equaliser and Merouane Zemmama's late winner.
Southampton -- five points clear of West Ham -- will now be keeping a keen eye on the Hammers' trip to Leicester on Monday when a defeat or draw for the east London club would seal promotion for Adkins' men.
Source: AFP
Source: AFP