Sánchez returned from the 2017 Confederations Cup with an injury, and therefore had to miss the team's victory over Chelsea in the 2017 FA Community Shield and the team's opening 4–3 win over Leicester City. Sánchez' first start of the season came in the 4–0 away defeat to Liverpool. But throughout the transfer window, there was increasing speculation about his future, with a huge amount of reports stating his desire to leave, in order to play in the Champions League. A deadline day move to Manchester City was unsuccessful as Arsenal's deal for Sánchez's replacement Thomas Lemar was rejected. He scored his first goal for the season in Arsenal's 3–1 UEFA Europa League victory over German side Köln, in which he picked the ball up outside the penalty area and curled a shot past goalkeeper Timo Horn, to score Arsenal's second goal of the evening. Sánchez also played in Arsenal's 1–0 win over Doncaster Rovers in the League Cup, in which Sánchez provided his first assist of the season, by delivering a cross-field pass which Theo Walcott subsequently put past Doncaster goalkeeper, Ian Lawlor.