Luke O’Nien had earlier put the Black Cats 1-0 ahead but the game was thrown into chaos when a powercut plunged the Estadio Municipal de Albufeira into darkness during the half-time interval.
Officials deliberated for nearly 45 minutes as they waited for the lights to come back on, before a decision was taken to cancel the match, much to the disappointment of the supporters who had travelled to the Algarve for the fixture.
Rangers confirmed the news in a short Twitter post which read: “Due to ongoing power outage, the match has been cancelled.
“We apologise to our supporters for the inconvenience and wish @SunderlandAFC the best for the upcoming season.”
The club later posted a statement, adding: “Neither Rangers or Sunderland were responsible for the stadium operations and the floodlight failure.
“However, Rangers appreciate the support of our loyal fans and the support they give the team everywhere we go which means everything to us.
“Rangers will refund the ticket cost to all Rangers ticket holders and our supporters that purchased the match on RangersTV. Thanks for your continued support.”
Rangers handed a debut to Antonio Colak following his £1.8m move from PAOK but there were few opportunities for the Croatian international in a cagey affair.
The game was preceded by a minute's silence in memory of legendary Rangers goalkeeper Andy Goram and winger Davie Wilson.