Arsenal booked their place in the knockout phase of the Europa League with two games to spare following a goalless draw against Sporting Lisbon at the Emirates on Thursday evening
The night will largely be remembered though because of a serious ankle injury sustained by Danny Welbeck which saw him  during the first half
His replacement, Pierre Emerick-Aubameyang struck the crossbar early in the second half but that was as close as the Gunners came to a winner as Sporting, who had Jeremy Mathieu sent off late on, held on for a point
The draw was enough to see Unai Emery's side, who extended their unbeaten run to 15 matches, through to the last 32 because of Qarabag's 1-0 win at Vorskla but they will have to wait until their next match - a trip to Vorskla on November 29 - for the chance to seal top spot in Group E
After a relatively quiet start in north London, the game burst into life when Matteo Guendouzi's low cross was almost turned into his own net by Mathieu, but with the ball trickling towards goal Sebastian Coates hooked the ball to safety
Arsenal were then dealt a huge blow when Welbeck fell awkwardly after going up for a header against Bruno Gaspar
 The 27-year-old, who has had his fair share of bad luck with injuries over the years, was eventually stretchered from the field with his team-mates visibly shaken by the extent of the injury
Welbeck was replaced by Aubameyang who nearly broke the deadlock minutes into the second half, getting across his man to meet Henrikh Mkhitaryan's low cross, but the striker's shot clipped the top of the crossbar
Sporting rarely threatened the Arsenal goal but in the 58th minute they served up a reminder as former Manchester United winger Nani burst past Aaron Ramsey and into the Gunners' half
 He pulled the ball back from the byline in search of Fredy Montero but Petr Cech read the pass, diving off his line to gather ahead of the striker
Arsenal suffered a further injury blow when Stephan Lichtsteiner pulled up with a suspected hamstring injury and he was replaced by Ainsley Maitland-Niles with 17 minutes remaining
The Gunners pushed for a winner but the game continued without any real chances of note, Mkhitaryan stabbing anAlex Iwobi cross towards goal before Aubameyang saw an effort bravely blocked
Aubameyang thought he had a late one-on-one to win it but was fouled by Mathieu, who was shown a straight red card for the cynical trip
 Aubameyang fired the resultant free-kick over the crossbar as Sporting held on
: "It's the worst news tonight, this injury
 It's clear that we are with Welbeck in these minutes
He was working well and he was having a good match
 He had some chances too
His injury was with the mentality of the players
 They saw it was a big injury
 When you are playing football, when you are playing in competitive matches, it can happen
 You don't want it to happen but this is our profession
 Now he is at the hospital
 The news is that we are going to wait - but we think it's a serious injury
": "The players did exactly what I asked them to do
 In our game plan we know we had to be rigorous and they were almost perfect on that
 We were aware of the opponent's quality but we, knowing our capacity and being creative and aggressive with and without ball, could try to surprise here
"It proved a frustrating night for the Gunners and the former Liverpool and Sunderland defender played a big part in that
He kept his side in it with a goal-line clearance in the first half after Mathieu diverted Guendouzi's cross towards his own goal line
He then put his body on the line during the second to make an excellent block to deny Aubameyang and help his side to a crucial point at the Emirates
Arsenal are back in Premier League action on Sunday when they take on Wolves at the Emirates Stadium (4
30pm)
 Next up in the Europa League is a trip to Ukraine to take on Vorskla (November 29, 5
55pm)
Sporting are back in domestic action on Sunday hosting Chaves in the Primeira Liga (8pm)
 Their next Europa League match is a trip to Azerbaijan to face Qarabag (November 29, 5
55pm)
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