Heather Watson
Watson battled admirably but fell agonisingly short against Kerber in Miami.Getty Images

Heather Watson was disappointed with her second-round exit at the Miami Open but insists that she is improving following a narrow loss to Angelique Kerber.

British number one Watson, who was facing Kerber for only the second time in her career, lost the first set 7-5 on Friday but an extended rain delay initially appeared to help her focus as she came out 24 hours later to take the second 6-3.

Despite battling back from a big deficit to level the deciding set at 4-4, Watson could not complete a rousing comeback and Kerber progressed to the third round where she will meet Svetlana Kuznetsova.

"I think I didn't strike the right balance today in when I should be patient and when I should be aggressive," Watson told BBC Sport after the match.

"I'm very disappointed in today. I felt it was a good opportunity for me, but I feel like I'm definitely improving as a player on the court with my tennis and mentally. I know I can compete with these girls and push them and beat them."

Elsewhere at the tournament, Novak Djokovic emerged victorious despite dropping the second set in his match with Slovakian Martin Klizan while fourth seed Kei Nishikori thrashed Mikhail Youzhny.

There were also victories for Jo-Wilfried Tsonga, David Ferrer, Fernando Verdasco and Gael Monfils in the men's draw. Andy Murray had already made sure of his place in the next round with victory over Donald Young on Friday (March 27) and faces Santiago Giraldo next.

Serena Williams, meanwhile, overcame knee trouble to sweep aside Monica Niculescu 6-3, 6-1 and set up a tie with Catherine Bellis.