AC Milan and Celtic players fight for the ball during the Europa League Group H first leg soccer match between Celtic and AC Milan at the Celtic Park stadium in Glasgow, Scotland, Oct 22, 2020. (JANE BARLOW / POOL VIA AP)

STOCKHOLM - AC Milan withstood a late onslaught to beat Celtic 3-1 and AZ Alkmaar overcame the loss of 13 players with positive COVID-19 tests to secure a shock 1-0 win at Napoli as the Europa League group stage got underway on Thursday.

London sides Tottenham Hotspur and Arsenal also made winning starts as did fellow Premier League club Leicester City.

Dutch team Alkmaar were under pressure for the whole game as Napoli dominated possession and peppered their goal but Dani de Wit scored in the 57th minute for a stunning victory in Group F.

AZ Alkmaar's Dani De Wit, center, celebrates his side's 1-0 win at the end of the Europa League group F soccer match between Napoli and AZ Alkmaar, at the San Paolo Stadium in Naples, Italy, Oct 22, 2020. (ALESSANDRO GAROFALO / LAPRESSE VIA AP)

With Milan’s defense well marshalled by Danish center-back Simon Kjaer, they looked to be cruising to an easy win at Celtic after first-half goals from Rade Krunic and Brahim Diaz.

However, the Scottish champions came roaring back in the second half and reduced the deficit through Mohamed Elyounoussi. Milan needed a late goal from Jens Petter Hauge, his first for the club, to put the Group H game out of reach.

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Kemar Roofe scored a superb stoppage-time goal for Rangers, bustling past three players from the edge of his own area before lobbing goalkeeper Arnaud Bodart from the halway line as his side won 2-0 at Standard Liege in Group D.

“The goal was a moment of genius -- a world-class moment. I have been playing football professionally since 1998 and it is the best goal I have ever seen live with my own eyes,” Rangers manager Steven Gerrard told Rangers TV.

Rangers' Kemar Roofe, left, celebrates with teammates after scoring his side's second goal during the Europa League Group D soccer match between Standard Liege and Rangers at the Maurice Dufrasne stadium in Liege, Belgium, Oct 22, 2020. (FRANCISCO SECO / AP)

Villarreal and Turkey’s Sivasspor played out an eight-goal thriller in Group I, with the Spanish side grabbing a 5-3 win thanks to a late double from striker Paco Alcacer.

Arsenal, who have not claimed a European trophy since lifting the old Cup Winners’ Cup in 1994, went behind at Rapid Vienna but defender David Luiz and striker Pierre-Emerick Aubameyang struck late on for a 2-1 Group B win.

READ MORE: Aubameyang says he considered Arsenal exit

Fellow Premier League sides Leicester City and Tottenham Hotspur cruised to comfortable 3-0 wins, with the Foxes downing visiting Ukrainian side FK Zorya Luhansk in Group G, while hosts Spurs beat Austrians LASK in Group J.

LASK's Marvin Potzmann, left, and Tottenham's Gareth Bale challenge for the ball during the Europa League, Group J soccer match between Tottenham Hotspur and LASK in London, England, Oct 22, 2020. (ADAM DAVY / POOL PHOTO VIA AP)

Tottenham’s fine performance, including an assist from Gareth Bale on his first start back at the club on loan from Real Madrid, spurred on the London side who lost the 2019 Champions League final to Liverpool.

“We went out there today and did a great job. We were solid and threatening and the most important thing in these games at the start is to get the three points,” Bale told BT Sport.

Bayer Leverkusen went on the rampage against French side Nice in a 6-2 victory that saw winger Karim Bellarabi score twice late on for the home side in Group C.

Roma's Gonzalo Villar, right, tackles Young Boys' Nicolas Moumi Ngamaleu during the Europa League group stage Group A soccer match between Switzerland's BSC Young Boys Bern and Italy's AS Roma, at the Wankdorf stadium in Berne, Switzerland, Oct 22, 2020. (PETER SCHNEIDER / KEYSTONE VIA AP)

AS Roma came back from a goal down to beat Swiss side Young Boys 2-1 away thanks to two goals in five second-half minutes by Bruno Peres and Marash Kumbulla in Group A.

Granada and Real Sociedad had 2-1 and 1-0 away wins over PSV Eindhoven and Rijeka in Group E and F respectively, while Benfica chalked up a 4-2 victory over Lech Poznan in Group D.