Chelsea captain John Terry has questioned claims that Diego Costa is struggling with a hamstring problem.
Blues manager Jose Mourinho recently revealed that the striker was being hampered in training by the persistent injury.
However, after scoring nine goals in nine games this season, Terry believes that Costa is showing no signs of a lack of fitness.
"I'm not sure where that's coming from," the defender is quoted as saying by Sky Sports News. "He isn't showing that in training. He looks sharp, he looks angry, he looks aggressive. He's fit and that's the main thing. Diego has been a nightmare for defenders."
Costa scored his ninth goal of the season on Sunday to help Chelsea earn a 2-0 win over Arsenal in the Premier League.