Majority leader Mitch McConnell on Tuesday said Republican candidates in the most competitive races across the country are in “a knife fight” to hold the Senate.

McConnell, speaking to reporters in Louisville, Ky., said it's "just a brawl in every one of those places."

The Kentucky Republican said he hopes "when the smoke clears we'll still have a majority in the Senate." He named nine states, including Tennessee and Indiana, as places where Senate races are "dead even."

Not long ago, 2018 was expected to be an easier year for Senate Republicans: Democrats were supposed to be playing defense as Senate candidates ran in conservative states that President Trump handily won two years ago.

But Real Clear Politics lists eight Senate races as toss-ups: Texas, Arizona, Indiana, Montana, Missouri, Florida, Tennessee, Nevada and North Dakota.

Some involve red state incumbent Democrats: Joe Donnelly in Indiana, Claire McCaskill in Missouri and Heidi Heitkamp in North Dakota.

GOP SENATE MAJORITY IN JEOPARDY? TIGHT RACES RAISE ALARM

But for Republican leaders seeking to maintain Senate control, some races are becoming a little too close for comfort. A prime example involves Texas Sen. Ted Cruz, a former presidential candidate who is now fighting to hold on to his seat.

“We’ve got a fight on our hands,” Cruz recently said. “The extreme left, they’re angry, they’re energized and they are filled with hatred."

Money has poured into Texas to benefit his challenger, U.S. Rep. Beto O’Rourke, D-El Paso, who is attracting large crowds at rallies.

"It's about the future of this country, the big things we want to do, going from the least-insured state in the country to the one that leads on universal health care," O’Rourke told supporters at a recent campaign stop.

Democrats are hopeful that the Senate majority is in play – energized by the numbers in Texas, Tennessee and other places.

But they acknowledge their incumbent senators must perform in what are expected to be hard-fought races.

“North Dakota, Missouri and Florida – three very close, very tough fights in very tough states for three members of the Senate, two of whom at least won during Obama's last election, where they had the benefit of him being at the top of the ticket,” Democratic strategist Mary Anne Marsh told Fox News.

Fox News’ Mike Emanuel and The Associated Press contributed this report.