SAN FRANCISCO -- A senior partner at a Silicon Valley venture capital firm says he was a loyal supporter of a woman who is now suing the company for sex discrimination.

Billionaire John Doerr took the witness stand for a second day on Wednesday in the lawsuit alleging women were denied chances to advance at Kleiner Perkins Caufield & Byers.

The lawsuit was filed by Ellen Pao, who says she was denied a chance to advance because she is a woman and was fired in 2012 after she complained.

Under questioning by Kleiner Perkins' attorney, Lynne Hermle, Doerr, a member of the firm's management team, said he fought for Pao to stay and objected when other partners wanted to let her go in 2011.

Doerr says he provided Pao with two coaches to help improve her skills.