Former UEFA Cup winners Valencia face a struggle to turn around their Europa League quarter-final against Basle after allowing the Swiss team to take a 3-0 first-leg lead.
Basle have never reached a major European final but showed their appetite for getting to a first as two goals from Matias Delgado put them in charge of the tie, ahead of next week's trip to Spain.
Argentinian midfielder Delgado, in his second spell at the club, was allowed too much space to unleash a fine shot from 20 yards into the bottom left corner for the 34th-minute opener.
Four minutes later Valencia failed to track him as the number 10 jabbed home Valentin Stocker's superb defence-bisecting cross from the left.
Stocker added the third in stoppage time, charging from the halfway line and cracking in a powerful strike.
The match at St Jakob-Park was played behind closed doors as a result of the trouble among Basle fans which caused the second leg of their 2-1 aggregate victory over Salzburg in the last round to be suspended for 13 minutes.
Valencia won the tournament in its previous guise 10 years ago, and they face seemingly the stiffest task of the teams who remain in this year's competition to reach the final four.
Leonardo Bonucci gave Juventus a 1-0 victory away to Lyon as the tournament favourites edged a tight tussle in France. Bonucci netted in the 85th minute, applying a powerful finish after a scramble for the ball inside the penalty area.
Porto put shaky form in the Portuguese Liga behind them to take a 1-0 lead over Sevilla, earned by a fine header from Eliaquim Mangala in the 31st minute. Porto will be without defensive midfielder Fernando for the second leg in Spain, after he was sent off for two late yellow-card offences.
Benfica, who beat Tottenham in the previous round and lead the Portuguese league, proved too strong for Dutch outfit AZ as they won 1-0 in Holland to take a grip on their tie.
Eduardo Salvio put Benfica in front after 48 minutes with a smart volleyed finish after goalkeeper Esteban palmed out a shot from Oscar Cardozo.