Boro gave goalkeeper Bradley Jones a rare first-team appearance and midfielder Josh Walker his first start for the club.
Non-league Barrow created a Riverside Stadium record before a ball was kicked.
7,000 of their fans packed one end of the stadium, by far the biggest away contingent since Boro joined the Premier League.
Barrow were given a tremendous welcome by their fans and there was a terrific atmosphere long before the kick-off.
Barrow refused to adopt a negative approach, it could have been easy for them to pack the midfield in an attempt to stifle Middlesbrough.
The visitors however went on the attack with controlled football and Boro certainly didn't have it easy in the early stages.
Alan Martin was the busier goalkeeper however as Middlesbrough began to settle and force the pace.
It was no surprise when Brazilian Afonso Alves put them ahead at 22 minutes from a Stewart Downing pass.
It ended a lean scoring spell by the club's record buy. He certainly must have welcomed his goal after being labelled a flop in recent weeks.
Middlesbrough suffered a blow after 33 minutes when Jeremie Aliadiere was carried off on a stretcher after lengthy treatment near the touchline.
England winger Downing was prominent in his new central midfield role. He shot wide on a couple of occasions and should certainly have increased the lead just before the break after creating a glorious chance.
A few minutes earlier Boro had a lucky escape when Michael Pearson struck a post with Ross Turnbull beaten.
Pearson, unfortunately suffered a blow just after the interval and was carried off on a stretcher with a leg injury.
Middlesbrough piled on the pressure but Barrow, to their credit, were putting up spirited resistance and refused to panic. Martin was excelling in goal and earning the applause of a 25,000 crowd.
Middlesbrough finally went further ahead after 62 minutes with Alves again the scorer and Downing providing the pass.
Barrow refused to give up the ghost and to a terrific roar from their jubilant supporters Jason Walker reduced the arrears after 79 minutes.
The goal provided for a tense finalem though Alves should have put the issue beyond doubt when he struck the post, before the referee ruled there were seven minutes of stoppage time to play.
Boro eventually held on, but every credit should go to Barrow for their battling performance and they fully deserved an ovation from a sporting crowd after the final whistle.