Atlético Madrid completed their easy win against Lazio in style. A Diego Godin goal shortly after halftime ensured a 1-0 home victory and a 4-1 aggregate lead over their Serie A opponents. Braga, last year's runners-up, weren't nearly so fortunate against Beşiktaş. After a 2-0 loss at home against their Turkish opponents, Braga needed two goals to avoid going out. They found one in the first half, but despite applying constant pressure, the match would remain at 1-0 and Beşiktaş advance on aggregate.
Metalist Kharkiv must have felt bad about demolishing Salzburg 4-0 in their home stadium, so they gave them a goal this time around. Of course, any sympathy the Ukrainians may have felt for their woeful opposition didn't stop them from scoring a second sackful of goals. Their 4-1 home win meant an 8-1 aggregate victory that was the standout scoreline of the first knockout round. Meanwhile, Olympiacos made their most of their 1-0 lead against Rubin Kazan from the first leg, striking early in the first half and holding on for a 2-0 aggregate win.
Schalke 04 would have had every confidence of advancing against Czech outfit Viktoria Plzeň, but despite going ahead early and seeing the visitors down to 10 men, the Germans were rocked by a very late equalizer from midfielder František Rajtoral that took the match to extra time. Klaas-Jan Huntelaar would save Schalke from the lottery of the penalty shootout, however, scoring shortly after the halfway point and then again in the 120th minute to give Schalke a 3-1 win on the night and a 4-2 aggregate victory.
Sporting Lisbon and Legia Warsaw had drawn 2-2 in Poland, meaning that a 0-0 draw would see the Primeira Liga side through. That's how it stayed for much of the match before Matías Fernández made sure of things for the hosts, scoring in the 84th minute to lead his side to a 3-2 aggregate win. Meanwhile, a Maarten Martens goal saw AZ Alkmaar add to their first leg lead with a 2-0 aggregate win against Anderlecht.
Atlético Madrid 1-0 Lazio (Atlético win 4-1 on aggregate)
Beşiktaş 0-1 Braga (Beşiktaş win 2-1 on aggregate)
Metalist Kharkiv 4-1 Salzburg (Metalist win 8-1 on aggregate)
Manchester United 1-2 Ajax (United win 3-2 on aggregate)
Olympiacos 1-0 Rubin Kazan (Olympiakos win 2-0 on aggregate)
Schalke 04 3-1 AET Viktoria Plzeň (Schalke win 4-2 on aggregate)
Sporting Lisbon 1-0 Legia Warsaw (Sporting win 3-2 on aggregate)
Anderlecht 0-1 AZ Alkmaar (Alkmaar win 2-0 on aggregate)