Over the past 10 days, Portugal have stumbled to a 2-2 tie against Tunisia and a scoreless draw versus Belgium without the Real Madrid talisman.
Ronaldo had taken a break after Real Madrid's victory over Liverpool in the May 26 Champions League final, reports Efe news agency.
Unaffected by steady rain at the Estadio da Luz here on Thursday night, Portugal seized control of the match from the outset and would have opened the scoring with a Ronaldo goal in the 10th minute if not for a highly questionable off-side call.
But seven minutes later 21-year-old winger Goncalo Guedes made the score 1-0 when he scored in the area off a headed pass by Bernardo Silva, who had received a long ball from William Carvalho.
The Euro 2016 champions then struck again in the 37th minute when Ronaldo received a ball on the left side and sent a cross into the area to midfielder Bruno Fernandes, who headed the ball past Algerian net minder Abdelkader Salhi.
The Portuguese onslaught continued after halftime when Guedes scored on a header off a pass from Raphael Guerreiro, a play that was almost identical to the Iberian nation's second goal.
Ronaldo was replaced by Andre Silva in the 74th minute, bringing an early end to the Portuguese captain's 150th appearance as a member of the national squad.
Portugal then nearly got a fourth goal in the 81st minute, although the score was disallowed when the video assistant referee called Guedes for a hand ball on the play.
Algeria, meanwhile, finally generated some offence with time winding down, producing two shots on goal that gave goalkeeper Rui Patricio a chance to shine.
The victory was a confidence booster for Portugal, which got its first win since a 2-1 friendly victory over Egypt on March 23.
Ronaldo and company will play their opening match at this summer's World Cup in Russia on June 15 against Spain, followed by two other Group B contests against Morocco on June 20 and versus Iran on June 25.
Algeria failed to qualify for the World Cup for the first time since 2006.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
