The defender, who was recalled from his loan spell at Stoke yesterday, went straight into Gareth Southgate's team and rewarded his manager with a priceless 40th-minute header which put them on the road to victory over FA Cup finalists Portsmouth.

Riggott headed off to the Britannia Stadium having effectively been told he had no future at Boro, but a man who at one point formed a solid central defensive partnership with Southgate under Steve McClaren grabbed his chance with both hands.

Turkey international Tuncay Sanli wrapped up a vital victory with a 53rd-minute header as a crowd of 24,828 breathed a collective sigh of relief.

It was just Boro's second league win in 11 attempts and once the dust settles, Southgate knows there are issues which need to be addressed.

For Pompey, who also lost to the Teessiders at Fratton Park earlier in the season, there is the prospect of their big day in the FA Cup to look forward to, although manager Harry Redknapp may be disappointed at the way in which their league campaign has rather petered out.

There was a feeling around the Riverside Stadium before kick-off that Boro should not still have been fighting for their top-flight status at this stage of the season, a theory to which Southgate did not subscribe in the run-up to the game.

In the event, there was a nervousness about his team as they attempted to put an end to the anxiety of recent weeks.

In a first-half of few chances, the hosts enjoyed the better of them with Sol Campbell having to block Tuncay sixth-minute effort and Jamie Ashdown's palming away Afonso Alves' follow-up.

The Brazilian drilled another effort just wide as the Teessiders recovered from a lacklustre start to dominate.

In truth, Pompey, who despite early chances for Glen Johnson and Milan Baros, who shot wastefully over the bar after 19 minutes, had the look of a side with a trip to Wembley on their minds.

They played neat football at times with Lassana Diarra particularly effective in central midfield, but lacked the cutting edge to make the most of Jermain Defoe and Baros up front.

As Boro gradually assumed control, it took a fine challenge by Diarra to deny Fabio Rochemback a 26th-minute shot at goal.

Then Riggott took over. The defender, who expected to line up for Stoke as they attempt to secure promotion to the top flight this weekend, found himself heading back to Teesside yesterday as Southgate brought his loan spell to a premature end.

The decision to name him in the starting line-up for the first time since November 11 paid off five minutes before the break when he rose to power home Stewart Downing's corner and ease the tension inside the Riverside.

Riggott might have added to his tally in first-half injury-time, but could only glance Rochemback's free-kick across the face of goal.

The visitors might have dragged themselves back into the game within four minutes of the restart when Hermann Hreidarsson was allowed to control Johnson's deep free-kick inside the penalty area and toe-poke a shot towards goal which a grateful Mark Schwarzer claimed easily.

But Boro extended their lead when Tuncay timed his run to meet another Downing corner and head home his eighth goal of the season.

Niko Kranjcar saw a 57th-minute shot deflected wide and George Boateng blocked a Defoe effort two minutes later, but their side's response was limited.

Kranjcar's 35-yard free-kick on the hour was not too far away from the target, but smacked of desperation, although he was unfortunate to see his shot fly just wide after he had stepped inside David Wheater three minutes later.

But for all the visitors threw at their hosts, they created few clear-cut openings with Boro defending with the kind of resilience they lacked at Sunderland last week.

Indeed, Downing could have cemented the win 12 minutes from time after being played in by Rochemback, but he could not beat Ashdown.

Defoe, who had endured a frustrating afternoon, unwisely got himself involved in a tussle with Emanuel Pogatetz as time ran down, but it was the Austrian and his team-mates who were smiling at the end.