On 8 October, in a 2018 World Cup qualifying match against Ecuador, Agüero sustained a hamstring injury early on and was carried off the pitch in tears. Agüero himself said he expected to be out for around four weeks (in which the derby against Manchester United was to be played), although several media outlets later claimed the injury would last for eight weeks. He returned on 21 November, scoring in a 1–4 home loss to Liverpool; this was his 85th Premier League goal, making him the top-scoring South American of all time in the division, ahead of his compatriot and former strike partner Carlos Tevez. On 16 April 2016, Agüero scored a hat-trick in a 3–0 win at Chelsea, ending with a penalty kick. He became the third visiting player to score a Premier League hat-trick at Stamford Bridge, and the fifth player to have three 20-goal seasons in the division. Three days later, he scored his 100th Premier League goal in a 1–1 draw at Newcastle. He reached the century in 147 games, second only to Alan Shearer who did so in 124. The goal was also his sixth against Newcastle for the season, making him just the sixth player in the Premier League era to have scored six goals against the same club in a single campaign. Agüero ended the 2015–16 Premier League season with 24 goals, one behind Golden Boot winner Harry Kane and level with Jamie Vardy. However, with his goals coming from 30 appearances, Agüero recorded the league's best goals to minute ratio.
