Olympiacos v Arsenal facts

Familiar foes in the UEFA Champions League group stage, Olympiacos and Arsenal meet for the first time in both the UEFA Europa League and a knockout tie, with the first leg taking place in Piraeus.

• Olympiacos competed in the UEFA Champions League during the summer and autumn, coming through three qualifying ties before claiming third place in Group B behind Bayern München and Tottenham Hotspur thanks to a closing 1-0 win at home to Crvena zvezda. Arsenal's third successive UEFA Europa League group stage campaign began with three straight wins but they stuttered thereafter and needed a late comeback at Standard Liège on Matchday 6 to qualify as Group F winners.

Previous meetings
• The clubs have been paired together four times in the UEFA Champions League group stage, and on every occasion Arsenal have staged the home fixture on Matchday 2 and Olympiacos the return game on Matchday 6.

• The first six matches between them – in 2009/10, 2011/12 and 2012/13 – all ended in home wins, but last time out, in 2015/16, the roles were reversed, Olympiacos winning 3-2 in north London only to succumb to a 0-3 defeat at home. Olivier Giroud's hat-trick enabled Arsenal to pip their hosts to the runners-up spot in the group on the head-to-head rule and therefore secure a 16th successive appearances in the UEFA Champions League knockout phase.

• Olympiacos's record at home to English visitors is W7 D4 L4, one of the drawn matches having taken place earlier this season when they came from behind to hold Arsenal's local rivals Tottenham 2-2 on Matchday 1 of the UEFA Champions League thanks to goals from Daniel Podence (now in England with Wolves) and Matthieu Valbuena, a penalty. Their last knockout phase tie against English opposition, in the 2013/14 UEFA Champions League round of 16, yielded a first-leg 2-0 win in Piraeus against Manchester United, only for ex-Gunner Robin van Persie to score a hat-trick as United won the return 3-0 at Old Trafford.

• Arsenal have won only three of their nine previous UEFA competition encounters in Greece, losing five. That 3-0 victory in Piraeus four seasons ago ended a five-game winless run in the country (D1 L4).

Form guide
Olympiacos
• Second in the 2018/19 Greek Super League behind PAOK, Olympiacos went from the UEFA Europa League third qualifying round to the round of 32, where, having memorably eliminated AC Milan in the group stage, they were knocked out by Dynamo Kyiv (2-2 h, 0-1 a).

• This season Olympiacos returned to the UEFA Champions League group stage, earning their 19th participation with convincing qualifying victories over Viktoria Plzeň, İstanbul Başakşehir and Krasnodar. However, after drawing that opening group game against Spurs, they lost the next four and were indebted to Youssef El Arabi's 87th-minute penalty in their final fixture at home to Crvena zvezda for the win they needed to leapfrog the Serbian champions into third place.

• This is Olympiacos's seventh appearance in the UEFA Europa League round of 32 – and fifth after finishing third in their UEFA Champions League group. They have won just two of the previous six ties at this juncture – against Rubin Kazan in 2011/12 and Osmanlıspor in 2016/17 – and have yet to progress beyond the round of 16.

• A 2-3 defeat by Bayern on Matchday 4 ended Olympiacos's ten-game unbeaten European run in Piraeus, which included six UEFA Europa League fixtures last term (W4 D2). However, they have won only one of their eight home fixtures in the knockout phase of this competition – the first of them, 1-0 against Rubin. Their record since then is D4 L3.

Arsenal
• UEFA Champions League ever-presents for 19 successive seasons from 1998/99 to 2016/17, Arsenal reached the UEFA Europa League semi-finals at the first attempt in 2017/18, losing to eventual winners Atlético Madrid, before going one step further and making it to last season's final, where they were defeated 4-1 by London rivals Chelsea.

• Fifth place in the 2018/19 Premier League secured a third successive UEFA Europa League group stage berth for the Gunners, and they appeared to be cruising to the round of 32 when they opened with big wins against Eintracht Frankfurt (3-0 a) and Standard (4-0 h). Forced to come from behind to beat Vitória SC 3-2 at home on Matchday 3, they then drew 1-1 in Portugal and lost 1-2 at home to Eintracht before squeezing through in first place thanks to two late goals in Liege after they had gone 2-0 down.

• Arsenal have won both of their previous UEFA Europa League round of 32 ties, but in different circumstances. In 2017/18 they won the first leg 3-0 in Sweden against Östersund before losing 1-2 at home; a year later they were defeated 1-0 at BATE Borisov but recovered to win the home leg 3-0.

• The 1999/2000 UEFA Cup runners-up are unbeaten in five European away games, winning three in a row before drawing the last two in Guimaraes and Liege. Their overall away record in the UEFA Europa League is now W10 D3 L4.

UEFA Europa League squad changes
• Olympiacos
In: Ousseynou Ba, Kostas Fortounis, Christos Liatsos*, Hilal Soudani
Out: Yassine Benzia (Dijon), Daniel Podence (Wolves), Miguel Ángel Guerrero (Leganés, loan), Yassine Meriah (Kasımpaşa, loan), Alexandros Voilis
*B List

• Arsenal
In: Cédric (Southampton, loan), Miguel Azeez*, Pablo Marí (Flamengo, loan), Eddie Nketiah*, Tom Smith*
Out: Joel López, Tyreece John-Jules (Lincoln City), Konstantinos Mavropanos (Nürnberg, loan), James Olayinka, Emile Smith Rowe (Huddersfield, loan)
*B List

Links and trivia 
• Three Olympiacos players have had brief spells in England – Omar Elabdellaoui (who started his career in Manchester City's youth team) at Hull City in 2016/17,  Andreas Bouchalakis at Nottingham Forest in 2017/18 and Hilal Soudani, also at Forest, in 2018/19.

• Arsenal defender Sokratis Papastathopoulos is a long-standing Greek international who started out in his homeland with Olympiacos's local rivals AEK Athens (2005–08).

• Valbuena and Arsenal striker Alexandre Lacazette are former Lyon (2015–17) and France (2013–15) team-mates.

• Arsenal's next victory in the UEFA Europa League will be their 23rd in the competition, setting a new record for an English club. They are currently level on 22 with Tottenham.

• Olympiacos overcame Panionios 4-0 at home last Saturday to remain unbeaten in this season's Greek Super League and two points ahead of defending champions PAOK at the top of the table. El Arabi scored twice to increase his tally to 17 league goals this term – the best in the division.

• Arsenal also won 4-0 at the weekend, at home to Newcastle United – their biggest Premier League win of the season.

The coaches
• Pedro Martins was named Olympiacos coach in April 2018, becoming the club's fifth Portuguese boss in six years after Leonardo Jardim, Vítor Pereira, Marco Silva and Paulo Bento. Martins had not previously worked outside his homeland, his last three spells in the dugout before the move to Greece having brought UEFA Europa League qualification for Marítimo, Rio Ave and Vitória SC. A holding midfielder, he was capped once by Portugal during a three-year spell with Sporting CP from 1995–98.

• Mikel Arteta left his position as Josep Guardiola's assistant at Manchester City on 20 December 2019 to become Arsenal's head coach, replacing another Spaniard, Unai Emery, and returning to the club where he had spent the final years of his playing career, the last two as captain. A versatile, composed central midfielder, he was born in the Basque country but started his career at Barcelona. It was in England, however, where he blossomed, playing over 200 games for Everton and joining the Gunners in 2011, helping them to two FA Cup triumphs before retiring in 2016 and going straight into coaching as Guardiola's right-hand man.

UEFA Europa League knockout debut for VAR system
Video Assistant Referees (VAR) will be deployed in the UEFA Europa League knockout phase. The decision was taken by the UEFA Executive Committee last September, following the introduction of the system in several UEFA competitions in the 2018/19 campaign.