Arsenal centre-back William Saliba was forced off the pitch against Liverpool just moments after the game started, as the Gunners' early-season injury crisis worsens.
Mikel Arteta's side were already weakened through the absence of Bukayo Saka and Martin Odegaard, who was only deemed fit enough for the bench.
Losing Saliba to an injury will prove another crushing blow to Arteta, who are looking to maintain their unbeaten start to the season at Anfield.
The incident occurred innocuously, with Liverpool striker Hugo Ekitike backing into the defender, who immediately hit the ground in pain and glanced to the substitutes bench.
William Saliba was forced off the field against Liverpool after less than five minutes
|REUTERS
The 24-year-old Frenchman was an ever-present for Arsenal last year, missing just one league game through injury. The season before he played every minute in the Premier League.
Fans took to social media to express their concerns, too, with one fan writing: "We are so unlucky..."
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Talisman Bukayo Saka was absent for the trip to Anfield due to an injury he picked up against Leeds last week
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Another said: "We need to have a serious conversation about Arsenal’s physios."
A third questioned boss Arteta, commenting: "Another injury and Arteta was forcing him to play with it."
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A fourth added: "So we’ve lost Saka, Odegaard and Saliba. Literally our 3 most important players. If we win this game the season is ours."
The substitution paved the way for Cristhian Mosquera to get a look-in after his £13million signing from Valencia.
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Cristhian Mosquera, a £13million signing from Valencia, was brought on to replace the French centre-back | GETTYThe 21-year-old made his debut for the Gunners in a cameo appearance as a sub against Leeds United during their 5-0 thumping last week - though this afternoon's match has much larger ramifications.
Arsenal are also set to be finalising a deal for Bayer Leverkusen defender Piero Hincapie to add to their ranks, for a reported €52million fee.
That deal could prove even more pivotal now, depending on the severity and longevity of Saliba's injury.
Despite the blow, Arsenal started the game off as the better team in a cagey affair, with Noni Madueke demonstrating his strengths and testing Alisson in the Liverpool net.