Portugal required an own goal from Maksim Medvedev to help them to an unconvincing 1-0 victory over Azerbaijan in their opening 2022 FIFA World Cup qualifying fixture in Turin.
The reigning European and Nations League champions dominated possession against Group A's bottom seeds on Wednesday but struggled to create many clear-cut chances.
Azerbaijan skipper Medvedev put into his own net eight minutes before half-time following a mix-up with keeper Sahruddin Mahammadaliyev and that proved to be the only goal.
Cristiano Ronaldo fired a third successive blank for Portugal at Juventus' Allianz Stadium, where the game was being staged due to coronavirus travel restrictions, but Fernando Santos' men ultimately picked up the win.
Azerbaijan, the designated away side, had drawn their last four matches by the same 0-0 scoreline and kept Portugal's attacking talents quiet for large swathes of the first half.
Mahammadaliyev denied Ruben Neves and Joao Cancelo in quick succession, while Domingos Duarte fired wide from five yards after bringing down a chipped pass from Ronaldo.
But Portugal's pressure told 37 minutes in when Mahammadaliyev raced off his line and punched a cross into Medvedev, the ball flying off the Azerbaijan skipper and trickling into the net.
Despite the introduction of Bruno Fernandes from the bench at half-time, the Selecao continued to toil in the final third against a side ranked 108th in the FIFA rankings.
Ronaldo was kept out by Mahammadaliyev on the volley and Bernardo Silva also tested the Azerbaijan keeper, but Portugal could not add a killer second goal.
That nearly proved costly 19 minutes from time as Anatolii Nuriev blazed over with plenty of the goal to aim for after stand-in keeper Anthony Lopes failed to deal with a ball into the box.
What does it mean? Improvement needed from Portugal
The main aim for Portugal this calendar year will be to retain their European Championship title in the rescheduled tournament at the end of the season.
In the longer term, Santos' side will be looking to qualify for next year's World Cup in as stress-free manner as possible and lift the trophy for the first time in their history.
They may have made it five wins in a row against Azerbaijan by an 11-0 aggregate scoreline with this victory, but this was far from a vintage performance and they find themselves level on points with Serbia - 3-2 winners against Republic of Ireland - after the opening round of Group A games.
Mahammadaliyev makes amends
Mahammadaliyev may have been responsible for what proved to be the decisive goal, but he was undoubtedly the best player on the field.
The Qarabag keeper made 14 saves in total, despite playing through the pain barrier after being clattered into in the first half, on what proved to be a frustrating day for Portugal.
Ronaldo fires another blank
Playing in familiar surroundings at the home of club side Juventus, this was supposed to be the game in which Ronaldo returned to scoring ways for his country after failing to net against France and Croatia.
The superstar forward had eight shots in total, but only three of those were on target and the impressive Mahammadaliyev was equal to each of them.
Indeed, Ronaldo was outshone on the day by Pedro Neto, who played four key passes - the most of any player on the field - despite being taken off after 63 minutes.
Portugal face second seeds Serbia in Belgrade on Saturday, the same day that Azerbaijan travel to Debrecen to take on World Cup 2022 hosts Qatar in a friendly.