Jude Bellingham rescued Real Madrid with a 94th-minute strike to earn the Spanish giants a 1-0 win over Champions League debutants Union Berlin on Wednesday.
Carlo Ancelotti's side, 14-time winners of the competition, were thwarted at every turn by their stubborn German opponents, who were only promoted to the Bundesliga four years ago, until Bellingham prodded home at the death.
The England international has started his Madrid career in stunning goalscoring form with six goals in six games for the club across all competitions.
Madrid seemed destined to take only a point after Union Berlin goalkeeper Frederik Ronnow frustrated them and Rodrygo and Joselu both hit the woodwork.
Real Madrid have only failed to score in one of their last 68 home matches in the Champions League, and on few occasions at the Santiago Bernabeu have they seemed as toothless as in the first half.
Without injured forward Vinicius Junior the Madrid attack has lacked dynamism in recent weeks, even as midfielder Bellingham's goals have earned them a 100 percent record in La Liga after five games.
The English midfielder made his Champions League debut in the competition for Madrid after his move from Borussia Dortmund in the summer.
Bellingham arrived after Madrid's thrashing by Manchester City in last season's semi-finals, a new star to help Madrid try to win the competition they crave the most.
Despite Madrid's illustrious history, the visitors were calm, composed and above all, well-drilled defensively, under Swiss coach Urs Fischer.
Record signing Robin Gosens warned his Union Berlin team-mates they could not play with "awe and fear" and they responded with a disciplined display.
Perhaps it should have been no surprise, with veteran Italian defender Leonardo Bonucci making his debut at the back for the visitors.
The German side sat deep, surrendered the ball to Madrid and succeeded in frustrating the hosts.
Joselu wasted Madrid's best chance in the first half, heading narrowly wide, while his team-mates were reduced to pot-shots from distance.
Madrid turned the screw in the second half as the minutes ticked away, with Ronnow making a superb save to deny Rodrygo at the near post, before the Br azilian cracked another effort against the woodwork.
Berlin's goalkeeper tipped Joselu header's against the post, while also denying veteran midfielder Luka Modric, given a rare start by Ancelotti.
Union Berlin were living on a knife-edge in the final stages, with Joselu swinging a leg at Bellingham's cross to direct the ball fractionally wide with Ronnow beaten.
Eventually Bellingham decided the game, in the right place at the right time as a deflected strike fell his way in the box and he stabbed home from point-blank range.