He lost the match easily because he had played a . . . . . . . five set match in the earlier round.

The correct answer is B. gruelling.

A gruelling match is one that is very tiring and demanding. It is often used to describe a sporting event that is long and physically or mentally exhausting. In the context of the question, the man lost the match easily because he was tired from playing a gruelling five-set match in the earlier round.

The other options are not as accurate. A sensational match is one that is exciting and thrilling. A wonderful match is one that is enjoyable and satisfying. A controversial match is one that is disputed or debated.