Rep. Jeff Flake easily defeated real estate investor Wil Cardon in Tuesday’s Arizona Senate GOP primary, setting up a battle with Democrat Richard Carmona this fall.

Flake led Cardon 70 percent to 20 percent with just 15 percent of the vote counted, according to the Associated Press.

A year ago, Flake was the frontrunner to succeed retiring Sen. Jon Kyl (R). In the spring, Cardon initiated a television ad campaign that at times was highly personal and negative. In the summer, Flake returned the favor and the race became increasingly nasty.

It was a highly contentious primary and put Members of the delegation on the spot. Eventually, though, most of the state’s establishment closed in and backed Flake.

“It was tough, but never close,” Kyl, who endorsed Flake, said earlier today about the primary.

Flake will face Carmona, a former U.S. former surgeon general, this fall in a race that has the potential to play a pivotal role in which party controls the Senate. Carmona was essentially unchallenged in the Democratic primary.

Carmona went up on the air today with a positive television ad that touted his careers in military, law enforcement and medicine. The spot was backed by a six-figure ad buy.

Democrats say the Cardon threat helped their fall strategy. Democratic Senatorial Campaign Committee Executive Director Guy Cecil put out a memo earlier today addressing the race and noting that the two campaigns are essentially at financial parity after the primary.

Roll Call rates the Arizona Senate race as Leans Republican.