Ronaldo had been a doubt after limping out of the weekend friendly loss in France, but his goal gave Portugal their first points after their shock home loss to Albania last month.
Also in Group I, Serbia's game against Albania in Belgrade was abandoned shortly before half-time due to what UEFA described as "a disturbance on the pitch".
Trouble flared in the Group I clash when a drone descended on the stadium trailing a banner which contained an image of the Albanian flag.
Albanian supporters had been banned from the match by UEFA on safety grounds.
Serbian player Stefan Mitrovic appeared to attempt to remove the flag, sparking a brawl among players, coaching staff and some supporters on the pitch.
English referee Martin Atkinson led the players off the pitch before UEFA confirmed on its official website that the match had been abandoned and that the circumstances will be reported to its control, ethics and disciplinary body.
John O'Shea marked his 100th senior cap for the Republic of Ireland by scrambling a last-gasp equalizer against Germany in Gelsenkirchen in Group D.
The world champions were still smarting from Saturday's 2-0 defeat in Poland but looked to have sealed the three points when Toni Kroos fired a low 71st-minute opener past David Forde.
Irish substitute Wes Hoolahan saw a late goal-bound effort blocked by defender Erik Durm before O'Shea pounced to prod home from close range with the last kick of the game.
In the same group, Gordon Strachan's Scotland withstood some serious late pressure to earn a gutsy 2-2 draw against Poland in Warsaw.
The Scots responded to Krzysztof Maczynski's 12th-minute opener by surging ahead with goals from Shaun Maloney and Steven Naismith.
Arkadiusz Milik equalised for the hosts in the 76th minute and substitute Sebastian Mila missed a glorious chance to win it for the Poles in the dying minutes.
Jamie Ward put the visitors in front early and Kyle Lafferty extended their lead after the break as Michael O'Neill's men made it three wins out of three.
Two second-half goals from Bogdan Stancu sawRomania to a 2-0 win over Finland in Helsinki, and Adam Szalai scored the only goal of the game asHungary edged a 1-0 win in the Faroe Islands.
In the only game in Group E, Switzerland cruised to a 4-0 win in San Marino with two early strikes from Haris Seferovic and further goals from Blerim Dzemaili and Xherdan
