While Arsenal and Atletico Madrid found their first legs pleseant, Michy Batshuaiyi was present to rescue Borussia Dortmund from a draw in the first leg his last minute tap proved vital for the men in yellow to go ahead with an advantage into the second leg.
Michy Batshuayi scored twice, the second goal arriving in stoppage time, to earn Borussia Dortmund a 3-2 comeback win over Atalanta in the first leg of their Europa League last-32 tie.
Elsewhere, Arsenal powered past Ostersund 3-0, Atletico Madrid thrashed Copenhagen 4-1 and Italian league leader Napoli slipped to a surprise 3-1 home defeat against Leipzig.
Batshuayi, who has been in sparkling form since joining from Chelsea on loan in the mid-season transfer window, helped host Dortmund record its first victory in European competition this season.
Dortmund hadn't won in eight previous appearances and only joined the Europa League after finishing third in its Champions League group.
Andre Schurrle put Dortmund ahead after 30 minutes, only for Josep Ilicic to score twice for the Italian visitors in the 51st and 56th.
Batshuayi equalized in the 65th before grabbing the late winner. The Belgian striker replaced striker Pierre-Emerick Aubameyang at Dortmund following his move to Arsenal.
"Michy is a real goal-scorer, it was a good move to bring him here," Dortmund manager Peter Stoeger said. "Things are looking good. He is well liked, fully integrated and our goals and his personal goals align."
NO TURF TROUBLE FOR WENGER'S GUNNERS
Arsene Wenger had expressed concern that his Arsenal team had never practiced, much less played, on an artificial surface like the one at Swedish side Ostersund. He needn't have worried.
Arsenal had little trouble easing to a 3-0 win thanks to an early strike by Nacho Monreal and passes by Henrikh Mkhitaryan that led to two more goals.
Monreal scored after 13 minutes when he pounced after a shot by Alex Iwobi was saved by goalkeeper Aly Keita.
Mkhitaryan, who joined Arsenal from Manchester United two weeks ago, intercepted a pass in the area before his cross went in off Ostersund player Sotirios Papagiannopoulos in the 24th minute.
Mkhitaryan then laid on the third goal for Mesut Ozil in the 58th minute before Arsenal goalkeeper David Ospina saved a stoppage-time penalty by Tom Pettersson.
"People wondered why we didn't practice (on the pitch) before but the warm-up is good to adapt to the speed of the ball, for technical ability and the accuracy of the passing," said Wenger.
"We adapted very well because we're at a good technical level. They were very nervous at the start and we took advantage of it."
Arsenal was without injured striker Alexandre Lacazette while Aubameyang is ineligible to play in the competition.
Winning the Europa League may be the best chance for Wenger's team to return to the Champions League next season.
Arsenal is sixth in the English Premier League, eight points behind Chelsea, which holds the fourth and last qualifying berth.
ATLETICO START STRONG
Atletico Madrid overcame an early deficit in Denmark and strolled to a 4-1 win over Copenhagen.
After Viktor Fischer's opener, Atletico responded with goals by Saul Niguez, Kevin Gameiro, Antoine Griezmann and substitute Vitolo.
Atletico has reached two Champions League finals since winning the Europa League in 2012. It returned to the continent's second-tier competition after a disappointing group phase in this season's Champions League.
Napoli is staring at an exit after falling 3-1 at home to Leipzig. Substiute Adam Ounas gave Napoli the lead in the 52nd minute but Leipzig fought back with a double by Timo Werner and another goal by Bruma. Leipzig is a distant second to Bayern Munich in the Bundesliga.