Mitch McConnell would face biggest challenge yet in Alison Grimes

LOUISVILLE, Kentucky (CNN) - Senate Minority Leader Mitch McConnell uses sports metaphors to describe why he should be re-elected and not sacked by Democrat Alison Grimes, who would be Kentucky's first woman senator.

"Change the U.S. Senate and make me the offensive coordinator instead of the defensive coordinator," McConnell said to a small but enthusiastic crowd in Bowling Green.

"Sports fans know you can score on defense, but it's hard. When you're on offense, you get to call the plays and set the agenda for Kentucky and for America. That's what makes a big difference."

Translation: After two straight elections in which GOP fumbles kept Republicans in the minority, McConnell has another chance at running the Senate as majority leader, but that won't happen if he's defeated here at home and knocked out of the game.

On the eve of primary day here, McConnell appears confident he has crushed his challenger from the right, Matt Bevin. But it remains to be seen how much of a toll the manpower and money he has spent against Bevin will take - whether it will weaken him in what is expected to be the toughest campaign against a Democratic challenger in the three decades he has been in office.

It is also unclear whether the Republicans who don't support McConnell in the primary will end up voting for him in the fall. McConnell's campaign points out that Republican primary voters largely rallied around Rand Paul after a divisive GOP battle in 2010 and hope the same will happen this year for McConnell.

Grimes, a 35-year-old attorney and Kentucky's secretary of state, has a classic campaign strategy against the 72-year-old, five-term Senate incumbent: it's time for change.

"We've had 30 years of failed leadership under Mitch McConnell; we cannot afford six more," Grimes declared emphatically to a packed house at her campaign headquarters here in Louisville.

To counter that, McConnell is using a classic strategy for a longtime incumbent. He is trying to paint his seniority as a plus and warn Kentuckians about the perils of a junior senator with little clout in Washington representing them instead of a potential Senate majority leader.

"My opponent, I certainly agree, is a new face, but a new face for what? New face for the status quo. Same majority leader, same agenda, no change at all. A new face for no change at all," McConnell argues on the stump.

But Grimes' full-throated assault on McConnell goes beyond a call for change. She is using McConnell's GOP leader status and his frequent moves to block legislation to make him the symbol of gridlock in Washington.

We put that to McConnell in a brief interview.

"What Kentuckians have to decide is which direction they want the country to take," McConnell told CNN.

"Do we want to go in a different direction, or do we want Harry Reid to continue to be the majority leader? Do we want a vote for Barack Obama in a state that he carried four out of 120 countries? That's what's really at stake in the fall election," McConnell told us.

Like Republicans all over the country, McConnell is trying hard to make this election a referendum on Obama, who lost Kentucky big in 2012 and is highly unpopular now.

The problem for McConnell is that he too has a high unfavorable rating, and Democrats here are hoping that will be his ultimate downfall.

But McConnell has already been working hard to soften his image with positive television ads.

He is also almost always accompanied at campaign stops by his wife, former George W. Bush Labor Secretary Elaine Chao.

At their appearance in Bowling Green, she introduced McConnell by calling him her "soul mate."

Republicans hope that helps another challenge he has in his race against Grimes: women.

Grimes is unabashed in her quest to get female voters to the polls by reminding them that she would be their first female senator, but also by ripping McConnell on issues relating to women, such as his opposition to equal pay legislation like the Lilly Ledbetter Act.

"I hope you will spread the word not just across Jefferson County but the Commonwealth of Kentucky that this woman, well, she's not an empty dress, she's not a cheerleader, she's not a rubber stamp, she's an independent Kentucky woman that stands on her own two feet," Grimes yelled to her crowd here.

When asked about what polls show is a wide gender gap between him and Grimes, McConnell turned to Obamacare.

"Women in Kentucky have been treated just as badly in this environment as men have. Obamacare, you know women are typically those who manage their family's health care. They've been adversely impacted by Obamacare in a serious way. Surveys indicate women object to Obamacare even more than men. I think it ought to be pulled out from the root of the grass, and we ought to start over. I know that's not the view of my opponent in the fall," McConnnell told CNN.

As for Grimes, she may be trying to make Washington's problems all about McConnell, but she also clearly knows she has to overcome deep opposition to the President by separating herself from him.

"This election is not a referendum on the President. Nothing about this election is going to change who our President is, but we can actually change who is in Washington, D.C., and put someone there who fights for the people of this state instead of looking out for his own job," Grimes told CNN.

She has been trying to aggressively criticize the President's policies on coal, seen in this coal-producing state as punitive.

Like other Democrats on the ballot this year, she sidestepped our questions about whether she would welcome the President's help.

She did, however, tell us she would love to campaign with Hillary Clinton, whom she called her "role model."

Grimes' father was a prominent supporter of President Bill Clinton during his campaigns and presidency. The former President, whom she called "family," has already been to Kentucky to raise money for Grimes.