Juventus scored late to beat Lyon 1-0 and take a big stride toward the Europa League semifinals.
Matias Delgado's two goals helped FC Basel to a 3-0 win over Valencia in a match played in an empty stadium on Thursday.
Portuguese teams Benfica and Porto also moved into strong positions after the first legs of the quarterfinals with 1-0 victories over AZ Alkmaar and Sevilla, respectively.
All the second legs will be played next Thursday.
Leonardo Bonucci poked home Juventus' winner after a goalmouth scramble in the 85th minute at Stade Gerland, keeping the Italian league leaders and competition favorites on course to reach the final in their stadium May 14.
But an ultimately successful night for Juventus was soured by the sight of Carlos Tevez leaving the pitch in the 55th minute with what appeared to be a groin strain.
Lyon battled gamely but was forced to retreat in the second half, with Sebastian Giovinco and Mauricio Isla having shots saved by Lyon's Anthony Lopes and Mirko Vucinic shooting over the crossbar for Juventus from inside the 6-yard box.
Just when it seemed Lyon would survive with a draw, Bonucci capitalized on a poor clearance from defender Bakary Kone to shoot into the top of the net from close range.
"We did not expect Lyon to defend that well," Juventus midfielder Paul Pogba said. "They surprised us in the first half. Things improved a bit in the second half, the team clicked."
Juventus is the only Italian club still involved in a European competition.
Delgado scored twice in five minutes and Valentin Stocker added a third goal in second-half stoppage time for Basel. UEFA ordered the first leg to be played without fans as punishment after Basel supporters temporarily stopped play during its 2-1 win at Salzburg two weeks ago for throwing fireworks on the field.
Benfica, beaten by Chelsea in last season's final, could be back in the title match next month after Eduardo Salvio's 48th-minute goal sealed a 1-0 win at AZ Alkmaar.
Porto beat Sevilla 1-0 at home thanks to Eliaquim Mangala's header from Ricardo Quaresma's superb cross in the 31st minute. Porto finished with 10 men after midfielder Fernando was given two yellow cards in a matter of seconds in the 87th minute for pulling an opponent's shirt and then kicking the ball away.
With Porto striker Jackson Martinez also missing the second leg because of suspension, two-time winner Sevilla is far from out of the home-and-away series.