HOUSTON (AP) -

Lt. Gov. David Dewhurst says he's confident he'll win a runoff against a state senator who is trying to unseat him from one of the most powerful offices in Texas state government.

Dewhurst will face Houston Sen. Dan Patrick in a May 27 runoff. Patrick and Dewhurst were the top two vote-getters Tuesday among a field of four candidates in the GOP primary. Patrick was leading Dewhurst Tuesday.

Dewhurst told supporters Tuesday evening in Houston that "this race is going into overtime and we are going to win it."

After 11 years as lieutenant governor, Dewhurst is facing the toughest re-election of his career.

All of Dewhurst's opponents had argued that he wasn't conservative enough. But Dewhurst said Tuesday he has the most conservative record in this race.