DENVER, Colorado, Oct 2, 2008 (AFP) - Republican White House hopeful John McCain told women at a rally Thursday that he was 'proud' of his vice-presidential pick Sarah Palin, hours before her televised debate with rival Democrat Joe Biden.

'In case you missed it, Governor Sarah Palin will have a debate tonight,' the Arizona senator told his audience in a hotel ball room.

'I can't tell you how proud I am of her,' he added about the Alaska governor mother-of five.

'My friends, she went against an incumbent governor of her own party. She took on her own party and the special interests,' added McCain, 72, referring to Palin's political exploits in the remote, arctic state.

'And again she took on the oil and gas industry,' he added.

'Sarah has a clear record of reform.'

The governor, 44, will face perhaps her biggest campaign trial late Thursday when she comes face-to-face with veteran Delaware Senator Biden, 65, in a televised debate at Washington University, in St. Louis, Missouri.

The only vice presidential debate of the campaign, it coincides with growing doubt about Palin's ability to fill the country's second-highest office among both the public and fellow Republican politicians.