On 8 November, Giroud registered his first goal of the season away to BATE Borisov in matchday four of the Europa League group stage. It was the only goal of the match, sending Chelsea through to the knockout stages of the tournament. In his next outing, he scored his first Premier League goal of the season in a 3–1 away loss to Tottenham Hotspur on 24 November. Giroud then made it four goals in three games, bagging a brace at home to PAOK in matchday five of the Europa League. Chelsea won the match 4–0. On his 500th career appearance, Giroud scored a free kick to equalise and preserve Chelsea's unbeaten Europa League group stage campaign. The match against Vidi at MOL Aréna Sóstó finished 2–2. Giroud scored his first Chelsea hat trick on 14 March in a 5–0 (8–0 aggregate) win over Dynamo Kyiv in the second leg of the Europa League round of 16 tie at NSC Olimpiyskiy. The following month, he became the first Chelsea player to score 10 goals in a single European campaign when he scored in a 4–3 semi-final second-leg win over Slavia Prague. In May 2019, he signed a new contract with Chelsea through the 2019–20 season. On 29 May, he scored in Chelsea's 4–1 win over his former club Arsenal in the Europa League final; during the match, he also set-up Hazard's second goal. With 11 goals in the competition, he set a new record for most goals by a French player in a single European season, breaking the previous record held jointly by Nestor Combin (achieved during the 1963–64 European Cup Winners' Cup) and Just Fontaine (achieved during the 1958–59 European Cup).