Arsenal's Bukayo Saka was seen shaking his head as he left the field with injury late on in their North London derby win over Tottenham Hotspur.
Saka provided the assist from a corner for Gabriel Magalhaes's header midway through the second half which won Arsenal all three points over the local rivals in the capital.
In what has been a very challenging start, going away to Aston Villa and Spurs, as well as facing an in-form Brighton & Hove Albion side, Mikel Arteta's men have come away with 10 points from their opening four games.
This was seen as the biggest challenge yet, as both Declan Rice and Martin Odegaard were unavailable due to suspension and injury, but Arsenal came through with flying colours.
However, with the return of the Champions League on the horizon this week, Arsenal could be without yet another key player ahead of the trip to Atalanta on Wednesday.
Bittersweet emotions for Arsenal as Saka limps off
In what was a perfect day for the Arsenal faithful, getting one over on their biggest rivals, the 1-0 victory may come with a costly price to pay.
Saka needed to be replaced by Ethan Nwaneri with five minutes remaining after falling to the turf in some discomfort.
The 23-year-old not only provided an assist for the game's only goal, but his work ethic along with fellow wide man Gabriel Martinelli helped the Arsenal rearguard keep Tottenham at bay.
Saka's excursions may have inadvertently led to the England man picking up a problem though, and the Gunners' faithful will now wait with bated breath for updates on the winger.
The goal contributions by Saka have been hugely important in Arsenal's strong start, and he currently tops the Premier League assist charts with four from four games.
Injury problems possibly mounting for Arteta's Arsenal
An injury to Saka will be the most unwelcoming of news to manager Arteta, who already lost Odegaard to an ankle injury suffered on international duty with Norway.
Riccardo Calafiori was also sidelined after picking up a knock while representing Italy against France last week, and fellow defenders Oleksandr Zinchenko and Takehiro Tomiyasu are also both out injured.
Arsenal fans are yet to see new big-money signing Mikel Merino either, as the Spaniard suffered a shoulder injury just days after completing his move from Real Sociedad.
The big positive is that Arteta will be able to call upon Rice again after he served his one-match suspension for a red card picked up against Brighton, and the midfielder is set to start in Bergamo this midweek.