The Real Madrid star and Portugal captain is now the all-time leading goalscorer in European Championship qualification and finals combined as his 23rd strike took him past Jon Dahl Tomasson and Hakan Sukur.
Ronaldo bundled the ball over the line 18 minutes from time to settle a scrappy affair at the Estadio Do Algarve to leave Portugal second in Group I.
One goal was also enough to settle things between Greece and Faroe Islands, with the latter clinching a hugely surprising victory in Athens.
Joan Simun Edmundsson got the winner just after the hour mark to ensure the minnows their first victory in qualifying since 2011.
It also ensured their first points of Group F as they moved above the 2004 European champions into fifth.
For Claudio Ranieri however, the result will likely lead to more unwanted pressure as they lost a third straight qualifier on home soil to sit bottom of the pack.
World champions Germany avoided what would have been the most unlikely of upsets as they brushed aside Gibraltar 4-0 at the Grundig Stadion in Nuremberg.
Germany coach Jachim Low had spoken of wanting a "big score" against a Gibraltar side made up largely of semi-professional and amateur players.
However, the world champions were limited to four, with a first-half brace from Thomas Muller and a Mario Gotze strike putting the hosts in control by half-time.
Yogan Santos' own goal rounded off the scoring after the hour to leave Germany second in Group D - three points behind Poland who were 4-0 winners in Georgia.
Kamil Glik, Grzegorz Krychowiak, Sebastian Mila and Arkadiusz Milik were all on target after the interval in Tbilisi to maintain the Poles' unbeaten start to the campaign.
Shaun Maloney applied the finishing touch to a slick short corner routine to help Scotland get past Republic of Ireland 1-0 at Celtic Park, while Northern Ireland fell to a 2-0 defeat against Romania - Paul Papp at the double for the hosts in Bucharest.
Zoltan Gera was Hungary's match-winner against Finland, while Nicklas Bendtner scored twice as Denmark came from a goal down to get past Serbia in their Group I encounter.
