Republican Mitt Romney's strong debate performance last week helped erase President Obama's lead in Virginia and change the outlook for the state's marquee Senate race, a new poll shows.

Romney and Obama are statistically tied in battleground Virginia, according to an NBC News/WSJ/Marist poll released Thursday. Romney had the support of 48 percent of the likely voters polled, and Obama had 47 percent, marking the first time in a month that Romney has shown significant momentum there.

About 7 percent of those surveyed in the latest poll said they chose a candidate after last week's debate, which was widely viewed as a Romney victory that has fueled a surge of support for him, particularly in swing states like Virginia.

The debate helped Romney pull ahead of Obama among independents and voters between ages 30 and 44.

Obama still holds a large lead among women voters but now trails Romney by 15 percentage points among men, up considerably from the 3-point gap the president faced earlier this month.

In Virginia's hotly contested U.S. Senate race, the new poll shows Republican George Allen has narrowed the lead of Democrat Tim Kaine and that the race is once again a virtual dead heat. A Marist poll last week showed Kaine with a 5-percentage-point lead, and Rasmussen Reports changed the race from "toss up" to "leans Democrat." Kaine leads in the new poll by just 1 point.

Kaine's campaign has been playing down any talk of him having an edge over Allen. Kaine said during a campaign stop in Northern Virginia that he's just trying to remain competitive against the heavy spending by outside groups on Allen's behalf.

"I feel like there's never momentum enough to feel good about with this super-PAC [spending]," Kaine said during a campaign stop in Northern Virginia this week. "The sheer amount of money from secret groups outside the state, largely false, that they're just pouring on TV keeps us very hungry, and we don't take anything for granted," he said.

Kaine and Allen, both former governors, are fighting to replace retiring Sen. Jim Webb, D-Va.

Allen's campaign circulated an internal poll Thursday that showed him with a 3-percentage-point lead over Kaine.

"Susan and I feel real good about it. It's going to be a tight race -- it's going to be really close," Allen said. "It's probably going to come down to about 10,000 votes like the last one did."