Cristiano Ronaldo was finally off the mark in the qualifying campaign, with Diogo Jota and Joao Palhinha also scoring to nullify Gerson Rodrigues' shock opener for the hosts.
Portugal struggling once again and seemed to be headed for another long night after falling behind. But they successfully clawed their way back into the game to take all three points.
To rub salt on Luxembourg's wounds, Maxime Chanot was sent off in the 86th minute for a second bookable offence, reducing the hots to a numerical disadvantage for the final few minutes.
Portugal are now top of Group A in their 2022 FIFA World Cup qualifying campaign. On that note, let's take a look at five talking points from the match:
#1 Cristiano Ronaldo ends a mini goal-drought for Portugal
At long last, Cristiano Ronaldo got the goal he was desperately waiting for the past few days.
After Joao Cancelo floated a lovely cross into the area, the Juventus ace stole in behind the Luxembourg defence and slammed home a confident finish.
It was nothing spectacular, though, and his performance wasn't top drawer on the night, either.
Nevertheless, the Portugal captain managed to find the back of the net, and that's what mattered to him, his team and his fans alike.
Ronaldo hasn't looked at his rip-roaring best for some time now. He saw a legitimate goal disallowed against Serbia. But he returned to scoring ways for Portugal for the first time in five games.
#2 Luxembourg show great potential
After beating Ireland in their first qualifying game against all the odds, Luxembourg were potentially on their way towards another one against Portugal.
The opening goal from Gerson Rodrigues summed up the side's encouraging performance in the first half.
Die Roten Lowen's high press appeared to throw their mighty visitors under the bus, while goalkeeper Anthony Moris handled their business well at the other end.
Even though Portugal's superior quality eventually made the difference, Luc Holtz's side can be proud of their efforts once again.
If they're able to continue in this vein in the upcoming games, Luxembourg could have a real chance of qualifying for the World Cup.