DENVER, Aug 11 (AP/UNB) - Democratic Sen. Michael Bennet has fended off a primary challenge from a rival who waged a relentless anti-establishment campaign.

Bennet was appointed last year and backed by the White House after predecessor Ken Salazar became Interior Secretary.

Bennet defeated former state Rep. Andrew Romanoff, who was backed by former President Bill Clinton. He will face either Ken Buck or Jane Norton in November in what will be a key race in the battle for control of Congress.

Bennet's appointment to the Senate angered many Colorado Democrats because he had never held public office before. Bennet was  superintendent of Denver Public Schools at the time.