Beatriz Haddad Maia claimed back-to-back WTA Tour titles after Zhang Shuai retired hurt in the Birmingham Classic final on Sunday.

Haddad Maia enjoyed a fine day, beating second seed and two-time major champion Simona Halep 6-3 2-6 6-4 in a rearranged semi-final (postponed from Saturday due to rain).

Zhang followed that up by battling past Halep's Romanian compatriot Sorana Cirstea 4-6 6-1 7-6 (7-5), setting up a second career match with Haddad Maia.

The Brazilian struggled in the opening stages, with Zhang racing into the lead before squandering an opportunity to go 3-0 up.

Haddad Maia soon recovered to level at 3-3 before Zhang was forced to retire with an apparent neck injury, with the Chinese player 5-4 down in the first set.

That handed the world number 32 her second straight title after success at the Nottingham Open last week, with Ons Jabeur and Iga Swiatek the only others to record multiple WTA Tour triumphs this year.

Haddad Maia also became the first Brazilian lift the trophy in the tournament's 40-year history, surpassing the previous best result by a player from Brazil when Gisele Miro made the second round in 1989.