Steaua Bucharest revived memories of its glory days in the 1980s by beating European champion Chelsea 1-0, while the prolific Gareth Bale inflicted more damage on Inter Milan to put Tottenham on the brink of the Europa League quarterfinals.
It was a chastening night for two recent winners of the Champions League in the last-16 first legs, with Chelsea slumping to a deserved loss in Bucharest when Raul Rusescu converted a 34th-minute penalty for Steaua.
Inter produced an even more inept display as Bale scored one goal and set up another for Jan Vertonghen in a 3-0 win for Spurs, tormenting the Italian side like he did three years ago in the Champions League when he first grabbed the attention of the footballing world.
Lazio and Basel will take 2-0 leads into the second legs of their matches against Stuttgart and Zenit St. Petersburg, respectively, while Benfica and Fenerbahce were also winners on Thursday.
The games between Anzhi Makhachkala-Newcastle and Levante-Rubin Kazan are delicately poised at 0-0.
Though it has never reached the same level again, Steaua was once a major force in Europe, winning the European Cup in 1986, reaching the same semifinals in 1988 before losing the 1989 final to AC Milan.
It was another memorable European night for the Romanian club on Thursday, hounding Chelsea into mistakes after receiving passionate backing by a record crowd of 55,000 in the National Arena and grabbing the winner after Rusescu was shoved in the back by Ryan Bertrand.
The center forward picked himself up and drilled home his spot kick.
Chelsea, which dropped into the Europa League after an unprecedented early exit from the Champions League group stage, was way below its best and the limp loss will pile more pressure on beleaguered interim coach Rafa Benitez — a figure of hate among many of the club's disgruntled fans this season.
"We are disappointed because we conceded a goal with a soft penalty and had one or two chances to score," Benitez said. "This result means we have to win at home and we have to push together."
Steaua, which is 12 points clear in the Romanian league, eliminated Ajax in the last 32.
Bale starred again for Tottenham by taking his tally to 11 in his past nine games in all competitions but it was a dominant team display, with Inter lucky not to come away from White Hart Lane with a heavier beating.
Bale capitalized on hesitant defending to open the scoring with a header in the sixth minute, before Gylfi Sigurdsson tapped in from close range to make it 2-0 in the 18th and Vertonghen added a third from Bale's inswinging corner eight minutes after halftime.
"It was a full 90-minute performance with excellent attacking football, reducing their chances and it was a great European night," Tottenham manager Andre Villas-Boas said. "(But) we are not through yet and the San Siro is a difficult place to go."
Bale blotted his performance by getting booked for diving in the first half, meaning he will miss the second leg.
Lazio has dropped off the pace in Serie A after losing four of its last six matches, but remains dangerous in Europe and was the better team from the start against Stuttgart.
Ederson gave the Italian side the lead in the 21st after Stuttgart twice failed to clear a loose ball, with the forward turning and sending a low shot inside the near post.
Onazi doubled the advantage in the 56th when he picked the ball in the center circle, beat one defender and surged into the area before clipping a neat finish past the advancing goalkeeper.
Basel will also think it has done enough to progress after scoring two late goals against Zenit, first through Marcelo Diaz and then by substitute Alexander Frei from the penalty spot in stoppage time after Luis Neto was red-carded for a foul on Mohamed Salah.
Pierre Webo was Fenerbahce's matchwinner in a 1-0 victory over Plzen while an unfortunate own goal by Bordeaux goalkeeper Cedric Carrasso gave Benfica a slim lead from their first leg.
Moreno Rodrigo's 25-yard shot crashed off the crossbar onto the back of Carrasso, with the ball rebounding into the net.
Levante and Rubin, the conqueror of defending champion Atletico Madrid in the last 32, both ended with 10 men in their match in Spain after Cristian Ansaldi's 52nd-minute red card for the visitors was quickly followed by another to Michel.