Barry had an evening to remember as the first phase of Capello's reign as England coach reached a satisfactory conclusion via a comfortable win in Port of Spain.
The Aston Villa midfielder scored his first goal for his country - eight years after his debut - and then was handed the captain's armband by Capello for the second half after David Beckham had been substituted.
Two goals from Defoe ensured the England players will head for their summer holidays in a positive frame of mind and the report on the first six months of Capello's reign should read "shows promise but still room for improvement".
Capello wanted to see how England would react away from home and in the kind of above normal temperatures that have proved difficult for them to deal with in major tournaments.
But the sun barely shone before darkness descended and in truth this represented little more than a glorified training exercise once Barry and Defoe had netted in the first quarter of the game.
And the cynical view remains this trip to the Caribbean represented little more than an exercise in trying to secure the backing of Trinidad and Tobago for the Football Association's expected bid for the 2018 World Cup finals.
That is why Capello probably started the game with his strongest available side when it would have been an ideal opportunity to give 90 minutes to the likes of Theo Walcott, Ashley Young and Gabriel Agbonlahor.
Now the work will start for real in September with England's opening World Cup qualifiers - away to Andorra in Barcelona and more importantly Croatia.
That is when Capello will be under the microscope for the first time as fans and critics alike wait to see if someone can finally get the best out of the so-called golden generation.
A new permanent captain should be in place for the final friendly international against the Czech Republic in August after Capello has tried out Steven Gerrard, Rio Ferdinand, John Terry and Beckham in the role.
Capello has had the chance to experiment for the past six months at different times with two holding midfield players, Wayne Rooney as the lone striker and Gerrard in a free role on the left side of midfield.
The players have had the opportunity to get used to Capello's methods and ways, which demand discipline and are different to his predecessor Steve McClaren.
The 23,000-capacity Hasely Crawford Stadium was almost full two hours before the kick-off despite England being without seven of the Manchester United and Chelsea players who had competed in the Champions League final.
They saw Beckham lead England out for for the 59th time - nearly two years after the last occasion in the 2006 World Cup.
The hosts, containing five English-based players in their side, were soon under the cosh and suffered an injury setback after only eight minutes.
Rio Ferdinand's hesitation forced David James to come racing out of his area and he collided with Sunderland striker Kenwyne Jones, who was carried off on a stretcher with a leg injury and replaced by Darryl Roberts.
Stewart Downing's ball picked out the overlapping run of Wayne Bridge and his first time cross was volleyed in at close range by Barry for his first goal for his country.
Then a pass from Downing was latched on to by Defoe, who had plenty of time to drill a low shot across Clayton Ince into the corner of the net.
The home side, who had held out for 83 minutes against England during the 2006 World Cup finals, showed plenty of spirit and Gerrard was booked for bringing down Khaleem Hyland after 29 minutes.
But a shot on the turn from Roberts, comfortably saved by James, was all they could manage and before half-time Defoe and debutant Dean Ashton volleyed over when well placed.
Inevitably Capello made a spate of half-time substitutions with David Bentley, Peter Crouch and debutants Joe Hart and Phil Jagielka replacing Beckham, Ashton, James and Ferdinand respectively.
And after 49 minutes Defoe struck for the second time after Crouch had headed a cross from Bentley into his path.
The Portsmouth striker should have completed a hat-trick but sliced his shot wide before making way for Theo Walcott with 20 minutes remaining.