When asked about the Djokovic/Murray collaboration, Sinner had no answer.

Is Novak Djokovic's choice of Andy Murray as his new coach causing a few teeth to grind? That's a possibility. What is certain is that Jannik Sinner's reaction when questioned on the subject will only fuel the rumors.

Questioned on the sidelines of the Davis Cup final against the Netherlands, the world number 1 simply refused to answer the question. A surprising reaction, but one that should soon be cleared up, as it's a safe bet that he'll be asked the question again.