PHOENIX — Rep. Martha McSally has lost a little ground in the GOP primary Senate race in Arizona, but she still has a healthy lead. She also still trails Democratic candidate Rep. Kyrsten Sinema, according to a poll released Wednesday.

The OH Predictive Insights/ABC15 poll of likely voters put McSally ahead 35 percent to 27 percent against Dr. Kelli Ward and 15 percent for former Maricopa County Sheriff Joe Arpaio.

Undecideds were at 23 percent.

In June, McSally led Ward 39.3 percent to 24.5 percent.

“The Arizona Senate contest is tightening and expect the attacks to ramp up as we head closer to election day,” Mike Noble, managing partner and chief pollster at OH Predictive Insights, said in a statement.

The primary was scheduled for Aug. 28. McSally, Ward, a former state senator, and Arpaio are running for the seat to be vacated by Sen. Jeff Flake, who is retiring after his term ends.

The poll showed that 89 percent of those surveyed said they were Republican and 11 percent said independent.

Respondents were called on July 23-25. Of the 576, the biggest group was age 55 and older (427).

Breaking down the overall group by ideology, double-digit figures were 36 percent said they were somewhat conservative, 33 percent very conservative and 12 percent leaned toward conservative.

The poll’s margin of error was plus or minus 4 percent.

In the potential general election match-up, Sinema, of Phoenix, continued to stay ahead of McSally, 48 percent to 44 percent.

“Things are going to be extremely different when Republicans choose a nominee — most likely Martha McSally — and the party unifies around that nominee,” Valley political analyst Stan Barnes told KTAR 92.3 FM’s Arizona’s Morning News.

“There will be $10 million of advertising explaining to voters what Republicans really think of Kyrsten Sinema.”

McSally, of Tucson, closed the distance with Sinema slightly from an April poll, when the margin favored the Democrat 48 percent to 42 percent.

Follow @KTAR923