Watford's Senegal international winger Ismaila Sarr could face a spell on the sidelines after suffering an ankle injury in the 2-0 win over Congo in the 2021 African Cup of Nations qualifier.
Sarr, 21, was taken off on a stretcher after he was replaced by Sada Thioub shortly after half-time and left the stadium on crutches with a protective cast around his ankle.
"Ismaila Sarr was diagnosed with a sprained right ankle and is scheduled to undergo further tests to determine the extent of the injury," Senegal's Football Federation said in a statement.
"This will also determine how long he is likely to be out of action for."
Sarr joined English Premier League side Watford as a club record signing from French outfit Rennes in the summer.
Despite marking his first Watford start with a goal in the League Cup win against Coventry, he has made just seven appearances in all competitions for the Hornets including five as a substitute.
Sarr, who has played 28 times for Senegal, won the Coupe de France with Rennes last season, scoring the decisive fifth penalty in their shootout win over Paris St-Germain.