Karim Adeyemi's stunning solo effort handed Borussia Dortmund a crucial 1-0 home victory over Chelsea in the first leg of their Champions League last 16 clashes, while Benfica cruised to a comfortable 2-0 away win at Club Brugge.
Wednesday's contest in Germany, the first competitive meeting between the sides, was edged by Chelsea on chances but only Adeyemi's speedy box-to-box run and finish on 63 minutes could separate them.
Dortmund have now won all seven matches across competitions in 2023.
Germany forward, 21, had flattered to deceive since signing from Salzburg in pre-season but has burst to life recently with two goals in the Bundesliga and what could be a crucial strike in Europe.
"It was a tough start, but we kept fighting," Adeyemi told DAZN. "I tried to win the one-on-one (with Enzo Fernandez) and the keeper came out, I had bit of luck and there we go. With our fans it was unbelievable. The win is very important for the second leg."
Benfica are in the box seat after Joao Mario's penalty and David Neres' late goal in Bruges, with the Portuguese wasting more chances.
The second legs are on March 7.
Bayern Munich won 1-0 at Paris Saint-Germain and AC Milan beat Tottenham Hotspur by the same score at home in Tuesday's first legs. The rest of the last-16 first legs are next week, including holders Real Madrid at Liverpool in a repeat of last season's final.
Dortmund's England midfielder Jude Bellingham, 19, was made captain for the second Champions League game this term, with Marco Reus on the bench as Edin Terzic preferred the more defensive Salih Özcan.
For Chelsea, left-back Ben Chilwell was back for the first time since pulling his hamstring in November.
Chelsea thought they had scored early on but Thiago Silva had palmed the ball into the net from a free-kick. He was shown a yellow card despite his protests that it was accidental.
Sebastien Haller, making his first Champions League appearance for Dortmund after cancer treatment, then went close.
Joao Felix soon missed two chances, including one which hit the bar, for a Chelsea side who have struggled in the Premier League of late.
The English side continued to be in the ascendancy early in the second half, Reece James twice testing Gregor Kobel.
Then out of nowhere, Adeyemi ran from his own box to Chelsea's in a stunning solo counter-attack before rounding Kepa Arrizabalaga to score from an acute angle.
Twice champions Chelsea pushed for an equalizer, having an effort cleared off the line, but 1997 winners Dortmund were dangerous on the break in a frantic last quarter, including a big touchline bust-up.
"I think our performance was good. We are a team coming together," Chelsea boss Graham Potter said. "It is half-time and we go to Stamford Bridge. We have to keep working."
In Belgium, Englishman Scott Parker took charge of this season's surprise packages Brugge in his first European game as a coach.
Benfica, bossed by German Roger Schmidt, had the better of the chances though as Rafa Silva hit the woodwork and Portugal World Cup star Goncalo Ramos was also a threat.
The hosts did have the ball in the net before the break but the video assistant confirmed Denis Odoi was offside.
The visitors broke the deadlock on 51 through Joao Mario's penalty, Simon Mignolet getting his hand to it but there was too much power.
Jack Hendry conceded the spot kick after fouling Ramos.
Substitute Neres extended the lead on 88 minutes as the twice champions put one foot in the quarter-finals.
Benfica midfielder Chiquinho told Eleven Sports: "We didn't start very well, but after 15 minutes we took over. We had several opportunities and in the end, we are fair winners."
