Sergio Aguero came off the bench to hand Manchester City the advantage in their Europa League tie against FC Porto, as they snatched a 2-1 win.
Highlights: Porto 1-2 Man City
The Argentinian struck from close range with six minutes remaining as City came from behind to condemn the Portuguese champions to a rare home defeat at the Estadio do Dragao.
The hosts took a 27th-minute lead in the first leg of the last-32 clash through Silvestre Varela but an Alvaro Pereira own goal gifted City an equaliser.
Ashley Young's first Manchester United goal since September set the Red Devils on their way to a comfortable 2-0 win over over Ajax in Amsterdam.
The last time Young found the net was a last-gasp consolation against FC Basel at Old Trafford, in a match which Sir Alex Ferguson still looks back on as the draw that cost his team their place in the Champions League.
And, after a poor first-half which needed David de Gea to rescue them, the visitors roused themselves after the break and Young's 58th-minute winner came at the end of their most threatening spell, the England man tucking home after Nani's cross had been deflected into his path.
Javier Hernandez added a second six minutes from time to secure a result that will allow Ferguson to take a pragmatic approach to next week's second leg.
Stoke will have to win in the Mestalla next week if their European adventure is to continue after Valencia shaded the first leg 1-0.
Mehmet Topal netted the only goal of the game in the 36th minute with a 30-yard screamer that gave Asmir Begovic absolutely no chance. Sofiane Feghouli also hit the post in the second half while Stoke, who have lost their past four Premier League games, were limited to half chances.
Falcao inspired Atletico Madrid to a come-from-behind 3-1 victory over Lazio in Rome to see the Spaniards take command.
Miroslav Klose put the home side ahead in the 19th minute before Falcao set up Adrian Lopez for the equaliser before the half-hour mark. The Colombian forward then put the visitors ahead in the 37th minute.
Falcao added his second after the hour mark to hand Atletico coach Diego Simeone, a former Lazio player, a winning debut in the Europa League.
Salzburg are all but out of the competition after a 4-0 drubbing by visitors Metalist Kharkiv.
They scored in the first and last minutes of the match through Taison and Bonfim Marlos, with Jonathan Cristaldo scoring a twice in three minutes in between.
Two quick goals ensured PSV Eindhoven claimed a 2-1 away win to give them control of their tie with Trabzonspor. Tim Matavz and Ola Toivonen stunned the home side with strikes inside the first 12 minutes.
Trabzonspor pulled a goal back through Olcan Adin on the half-hour and, while they controlled possession for long periods, their horror start proved costly as they failed to find a leveller.
Lokomotiv Moscow took the win but surrendered an away goal in a 2-1 success of Athletic Bilbao. Iker Munain put the Primera Division side in front but second-half strikes from Felipe Caceido and Denis Glushakov (penalty), reversed the result.
Schalke drew 1-1 at Viktoria Plzen, Klaas Jan-Huntelaar equalising Vladimar Darida's first-half effort.
Jan Schlaudraff's penalty 10 minutes from time earned Hannover a 2-1 victory over Club Brugge. The Bundesliga side, who are still unbeaten at home in their maiden Europa League campaign, fell behind to a Maxime Lestienne header early in the second half.
Substitute Artur Sobiech bundled home the equaliser after 71 minutes before Schlaudraff settled an action-packed encounter from the penalty spot.
Legia Warsaw and Sporting also drew 2-2 in Poland, with the Portuguese side equalising twice through Daniel Carrico and Andre Santos after goals from Jakub Wawrznyiak and Janusz Gol.
In Holland, AZ Alkmaar edged Anderlecht 1-0 courtesy of Adam Maher's 35th-minute shot.
FC Twente claimed a vital 1-0 away victory thanks to Ola John's lobbed winner as Steaua Bucharest failed to make home advantage count.
John's wonderful finish, which just crept in at the far post, was by far the highlight of an otherwise poor match that had few clear chances at either end. But Twente boss Steve McClaren will not mind as his side left the National Arena in control of the tie.
Gohi Bi Zorro Cyriac put Standard Liege ahead, but the Belgian side were pegged back in the 88th minute by a goal from Wisla Krakow's Tsvetan Genkov to claim a 1-1 draw.
Udinese were held to a goalless draw by PAOK Salonika as the absence of injured captain Antonio Di Natale told.
Di Natale, top scorer in Serie A with 17 goals was missing with a foot injury, and while the Italians created plenty of chances for his deputy Antonio Floro Flores, he was unable to find the net with any of them.