Barnsley lead Middlesbrough 1-0 at half time in their Championship clash at the Riverside Stadium.
The visitors took a surprise lead in the sixth minute when Jim O'Brien was played behind the Middlesbrough defence and his deflected shot looped over Jason Steele into the net.
Boro struggled to get a grip on proceedings and could have been two behind if not for Steele, who made a good save to deny Marlon Harewood.
Tony Mowbray's side continued to put in a disjointed display as the half neared its end and struggled to put the Barnsley goal under any pressure.
