Ronaldo scored just once at last year's World Cup, and there had been doubts over whether he would return for Portugal's Euro 2024 qualification campaign.
But having been named as captain in Martinez's starting XI for Thursday's match at Estadio Jose Alvalade, Ronaldo scored twice in the space of 12 minutes – a cool penalty followed by a wicked free-kick – to help cap an emphatic win and mark his record appearance in style.
Ronaldo's goals followed strikes from Joao Cancelo and Bernardo Silva as Portugal got off to the simplest of starts in Group J.
Liechtenstein's resistance lasted just eight minutes. The visitors failed to clear their lines following Bruno Fernandes' corner, and Cancelo's deflected strike from the edge of the area squirmed under Benjamin Buchel.
Ronaldo squandered two golden opportunities to extend Portugal's lead, firing over when one-on-one with Buchel before sending a free header wide.
Portugal's wait for a second ended 68 seconds after the restart, Silva on hand to tuck home after a cross was blocked into his path, and Ronaldo had his goal four minutes later.
Jens Hofer clumsily felled Cancelo, with Ronaldo drilling the resultant penalty into the bottom-left corner.
The offside flag cut Ronaldo's celebrations short when he prodded in from close range, but a superb 63rd-minute free-kick had too much power on it for Buchel.
There was no hat-trick for Ronaldo, who made way in the 78th minute, with the job done for new boss Martinez.