MOSCOW: Arsenal overcame a scare against CSKA Moscow Thursday to reach the Europa League semifinals, while Salzburg staged a stunning comeback to knock Lazio out with four goals in a 20-minute burst.

Played at a time of growing political tension between the Russian and British governments, there was no sign of trouble on the streets outside the VEB Arena in Moscow.

CSKA went 2-0 up to put Arsenal under pressure but the London club hit back to draw 2-2 on the night and progress 6-3 on aggregate.

Lazio seemed poised to clinch a place in the last four when Ciro Immobile struck in the 55th minute to give the Italian team a 5-2 advantage on aggregate.

Salzburg, though, produced a spectacular recovery to become the first Austrian team to reach the semifinals of the competition in its current form.

Marseille also qualified after losing the first leg, beating Leipzig 5-2 to win 5-3 overall, while Atletico Madrid lost 1-0 at Sporting Lisbon but scraped through 2-1 on aggregate.

Thursday's Europa League fixtures continued a week of dramatic Champions League comebacks, after Roma beat Barcelona and Juventus came close to knocking out Real Madrid.

Arsenal manager Arsene Wenger said it was a sign European competition is becoming more evenly matched. "The games are very open and everything is possible in every game," he said.

The Europa League semifinal draw will be on Friday.

Here's a look at the action:

ARSENAL THROUGH

Arsenal had to show some second-half grit to help Wenger move within three games of winning his first European trophy.

Wenger's team initially struggled on a cool spring night in Moscow, going 2-0 down after 50 minutes following goals from Fedor Chalov and Kirill Nababkin.

Danny Welbeck came to the rescue with a 75th minute goal before Aaron Ramsey went charging through the middle of the defense to grab Arsenal's second goal in stoppage time and extend his team's unbeaten run to seven games in all competitions.

Wenger said Arsenal's three-goal lead from the first leg had led to complacency. "When you have a big difference from the first game, it's hard to turn up with the same urgency," he said.

Despite the political tension between Russia and Britain over the poisoning of former spy Sergei Skripal last month and this week's developments in Syria, there was no sign of anger outside the sold-out VEB Arena.

The game was the last major European fixture to be played in Russia ahead of the World Cup and highlighted the country's strategy of flooding city districts with security forces.

There was a heavy police presence outside the ground and in much of the surrounding areas, with officers lining the streets and keeping fans in the open by barring access to alleyways.

With Arsenal sixth in the Premier League, 13 points off fourth place, winning the Europa League is its best chance of a Champions League spot next season.

SALZBURG ENERGETIC

The UEFA organizers had been faced with the awkward prospect of two Red Bull-branded teams, Salzburg and Leipzig, meeting in the semis and a resulting conflict of interest.

But it was the lesser-known of the two clubs that made the semis, with Salzburg taking advantage of a shock Lazio collapse.

Munas Dabbur, Amadou Haidara and Hwang hee-Chan were on target for the home team before Stefan Lainer capped a remarkable four-goal flurry when he netted with a diving header in the 76th minute.

MARSEILLE RALLY

In France, Leipzig went into the game against Marseille with a one-goal lead and opened up a 2-0 advantage on aggregate thanks to Bruma's second-minute goal.

However, Marseille hit back via an own goal from Stefan Ilsanker and strikes by Bouna Sarr and Florian Thauvin.

Leipzig regained the advantage with Jean-Kevin Augustin's curling 55th-minute shot before Marseille scored again through Dimiti Payet and Hiroki Sakai.

ATLETICO ON TRACK

Atletico remains on course for a third European final in five seasons after holding off Sporting.

Fredy Montero's 28th-minute header gave the home crowd hope in Lisbon but Atletico held on with the help of Jan Oblak's excellent goalkeeping.