The top seed Indo-Zimbabwean pair were no where near to their best as Knowles and Groenefeld, seeded ninth, took one hour and 28 minutes to overcame their fancied opponents 7-5 6-3.

After their triumph in the US Open last year, Paes and Black had a poor run in the circuit, making second round exits from both the Australian as well as the French Open.

The Indo-Zimbabwean pair, who had a more or less easy run en route the final here, clearly lacked on-court chemistry and made numerous unforced errors that cost them dearly.

Contrary to the result, Paes and Black started the match on a confident note and broke their opponents twice in the opening set -- fifth and seventh game -- to race to 5-2 lead.

But riding on the top seed's unforced errors, Knowles and Groenefeld clawed their way back into the match and won five consecutive games, which includes a double break in the ninth and 11th games, to pocket the first set 7-5.

With the momentum in their favour, Knowles and Groenefeld continued their aggressive play and seized the initiative early in the second set, breaking Paes and then holding their own serve to take a 3-0 lead.