[6] Arsenal later spent a club record £46.5 million on the French striker Alexandre Lacazette, who joined from Ligue 1 side Lyon.

[9] During the January transfer window, Arsenal signed Greek defender Konstantinos Mavropanos, who joined the club from PAS Giannina.

Mkhitaryan left Manchester United only 18 months after José Mourinho bought the winger from Borussia Dortmund; on the club website the player said it was a "dream" to join Arsenal and he looked forward to making history.

[12] Arsenal once again surpassed their club record transfer fee when they signed Gabon international Pierre-Emerick Aubameyang from Borussia Dortmund on deadline day for £56 million.

[13] Also in January, Arsenal let go of long-term forward Theo Walcott,[14] defender Mathieu Debuchy,[15] and high-profile striker Olivier Giroud, who joined London rivals Chelsea for £18 million.

Fans were divided in their opinions of the veteran manager, and discontent among players, notably Sánchez and Özil, became major talking points in the media before the season began.

[20] Following a penalty win over Bayern and a thorough defeat against Chelsea,[21] Arsenal returned to London to host the Emirates Cup at the club's home stadium which featured Benfica, Sevilla and RB Leipzig.

Danny Welbeck levelled the score just before halftime, but Vardy restored Leicester's lead with a header from Riyad Mahrez's corner.

Wenger's inspired substitutions then sparked Arsenal's comeback, with Aaron Ramsey firing in an angled drive and Giroud sealing the victory with a powerful header from Granit Xhaka's corner.

A brace from Welbeck and a curled finish from Lacazette allowed Arsenal to secure a comfortable victory over their struggling opponents at the Emirates.

[34] After a solid 2–0 victory over Brighton & Hove Albion on 1 October,[35] Arsenal traveled to Vicarage Road, where Per Mertesacker's header initially put them ahead against Watford.

However, a controversial penalty converted by Troy Deeney and a late winner from Tom Cleverley handed Arsenal a 2–1 defeat at Vicarage Road.

Monreal, Özil, Lacazette, Ramsey, and Sánchez all scored in a 5–2 victory, with Everton's goals coming from Wayne Rooney and Oumar Niasse.

Kevin De Bruyne opened the scoring for the hosts after a clever exchange with Fernandinho, firing a low shot past Petr Čech into the far post.

Substitute Lacazette pulled one back for Arsenal, but Gabriel Jesus sealed the victory for Manchester City with a close-range finish.

Stephan Shemilt of BBC Sport noted that Arsenal lacked "incision and creativity," with Sánchez often isolated as a lone forward without adequate support.

Antonio Valencia capitalised on an early mistake to put the visitors ahead, and Jesse Lingard quickly doubled their lead.

David de Gea delivered a world-class performance, making 14 saves to equal a Premier League record and denying Arsenal multiple chances to get back into the game.

[41] Following draws against Southampton and West Ham United,[28] Arsenal slipped to seventh on the table, marking their first winless streak of three league matches since April.

Philippe Coutinho opened the scoring with a header from Mohamed Salah's chipped pass, and the Egyptian doubled Liverpool's lead early in the second half.

Jack Wilshere opened the scoring in the 63rd minute, but Eden Hazard quickly equalised from the penalty spot after being fouled by Bellerín.

[50] Optimism returned at the Emirates following the January transfer window, when new signing Pierre-Emerick Aubameyang made an immediate impact, scoring on his debut in a 5–1 win over Everton, with Ramsey netting a hat-trick.

[51] However, their resurgence hit another setback in mid-February, as Arsenal lost 1–0 to rivals Tottenham Hotspur at Wembley Stadium, extending a difficult stretch in the Premier League.

[52] In early March, Arsenal suffered back-to-back defeats, first to Manchester City at the Emirates and then to Brighton & Hove Albion at Falmer Stadium.

Against West Ham next time, Monreal had his 52nd-minute strike cancelled out by Marko Arnautović, before Ramsey restores Arsenal's lead late on.

Things worsened next time out, as, despite Henrikh Mkhitaryan scoring on his return to Old Trafford, goals in either half from Paul Pogba and Marouane Fellaini saw Manchester United earn a 2–1 victory over the struggling Gunners.