Who directed the Oscar nominated 2004 film "Sideways", staring Paul Giamatti?

Explanation

Paul Giamatti was born in 1967 and studied at Yale University. He only started acting in the beginning of the 1990s. He broke through with his supporting role in "Man on the Moon" from 1996. He was nominated for an Academy Award for his role in the 2006 film "Cinderella Man" where he stars opposite Russel Crowe and Renée Zellweger. Giamatti is often cast in supporting roles but once in a while, he plays the lead. An example is Alexander Payne's "Sideways" from 2004 where he plays a frustrated man who is passionate about wine - this despite the fact that in real life, Giamatti has admitted to not knowing anything about wine.