Quarter-finals: first-leg facts and stats

• The first legs of the UEFA Europa League quarter-finals brought victories for all four teams that crossed over from the UEFA Champions League after the group stage – FC Basel 1893, SL Benfica, Juventus and FC Porto. Furthermore, each of the quartet kept a clean sheet.

• In winning their matches, Basel, Benfica, Juventus and Porto all retained their undefeated record in this season's UEFA Europa League, extending the sequence to five games. Benfica and Juventus share the best record, with four victories and one draw.

• AZ Alkmaar's 1-0 home loss to Benfica ended the last unbeaten run of a club that came through the UEFA Europa League group stage, bringing it to a halt at ten matches. It was also their first defeat in 12 UEFA Europa League home fixtures – a streak that began in December 2010.

• Valencia CF's 3-0 reverse at Basel prevented them from setting a new record of five successive clean sheets and from equalling the competition high of six consecutive away wins, while Sevilla FC's 1-0 loss at Porto was their first away defeat in this term's competition, ending a run of six games, eight including qualifying and play-off matches.

• Only six goals were scored in the four first-leg fixtures, a competition low by some distance. The four previous campaigns had yielded, respectively, 13, 19, 15 and 14 goals at the same juncture.

• Just once previously, in 16 quarter-final first-leg matches, had a team failed to score at this stage – SS Lazio in a 2-0 reverse at Fenerbahçe SK last season. This term no fewer than four sides failed to find the net, with AZ and Olympique Lyonnais becoming the first two quarter-finalists to draw a blank at home.

• With their respective victories in Alkmaar and Lyon, Benfica and Juventus became only the second and third clubs to win away from home in the first leg of a UEFA Europa League quarter-final. That feat had previously been achieved exclusively by Athletic Club with their 4-2 success at FC Schalke 04 in 2011/12.

• Basel's 3-0 triumph was the biggest at this point in the competition for three years, the 2010/11 campaign having produced two 5-1 scorelines, in favour of Porto and Villarreal CF. These remain the largest quarter-final first-leg victory margins.

• Benfica's win at AZ, their first in four quarter-final away fixtures, was their 23rd in the UEFA Europa League, matching the competition record set by Club Atlético de Madrid. Benfica's victories have come in fewer games, however – 34 to 38.

• Eduardo Salvio, who extended his record mark of UEFA Europa League appearances to 38, scored the winner at AZ that enabled Benfica to join PSV Eindhoven as the tournament's all-time top-scoring team with 64 goals. Again, the Portuguese club's record-equalling mark has been established in fewer matches – 34 to PSV's 42.

• Juventus's 1-0 success at Lyon was their 11th straight UEFA Europa League game without defeat – a sequence stretching back to a 4-1 loss at Fulham FC in the 2009/10 round of 16. It is the joint-second best unbeaten run in the competition's history, but they will need to maintain it all the way to (and including) the final in order to match Atlético's competition high of 15.