Diego denied England a morale-boosting opening night victory at the new Wembley Stadium as the substitute's stoppage-time equaliser earned Brazil a 1-1 draw with Steve McClaren's side.John Terry looked to have given the home side a much-needed shot in the arm ahead of next week's must-win Euro 2008 qualifier in Estonia as he headed home David Beckham's second-half cross to score the first England goal at the newly rebuilt stadium.
But Diego, who replaced the more illustrious Robinho 15 minutes from full-time, was in the right place at the right time to head home a cruel equaliser two minutes into stoppage time to end a disappointing game on a sour note for the near 90,000-crowd packed inside the national stadium.
McClaren had made the headlines during the week for his decision to recall Beckham almost 12 months after dumping the former captain following last year's poor World Cup campaign.
But the Real Madrid midfielder responded with a committed display capped by his superb 68th minute assist.
Beckham produced a trademark free-kick to the back post where Terry - ironically his replacement as captain - rose highest to head emphatically past Helton in the Brazil goal to open the scoring.
Earlier, Beckham had whipped a 30th minute free-kick across the face of goal and Ronaldinho had responded in kind with a similarly close set-piece in an even first 45 minutes.
Brazil though should have taken the lead on 20 minutes when Gilberto Silva looped a header over Paul Robinson only for the Arsenal midfielder to be incorrectly flagged offside as he met Robinho's chipped pass.
After the interval, Robinson denied a largely unimpressive Brazil with a superb one-handed save to divert Ronaldinho's low shot over the crossbar despite the ball taking a wicked deflection off the outstretched boot of Ledley King.
But England slowly built and on the foundations of a solid defence - in which Reading's Nicky Shorey was making his international debut - began to look more of an attacking threat with Steven Gerrard impressive in midfield.
First Michael Owen rippled the roof of the net with a flicked header and then substitute Stewart Downing tested Helton with a 25-yard drive seconds after making his entrance.
England capped their spell of pressure with Terry's opening goal, but then succumbed to a sucker-punch deep into stoppage time after Diego was left unmarked in the penalty area to head home from Gilberto's Silva cross.
Brazil should arguably have been level before that moment as Robinson punched a free-kick against an opposition player and was relieved to see it roll away to safety, while substitute Alfonso wasted a glorious chance with a close-range header over the bar with two minutes left on the clock.