Democrat Tim Kaine now holds a commanding lead over Republican George Allen in Virginia's U.S. Senate race even as the presidential race remains very close, according to a new poll.

Rasmussen Reports' latest survey of likely voters released Friday shows Kaine with 52 percent and Allen with 45 percent. It's the first time this poll has shown either candidate crossing the 50-percent threshold, and with so few undecided and 91 percent expressing certainty that they will vote next month, Rasmussen is now upgrading the race from "toss-up" to "leans Democrat."

A poll conducted in September showed Kaine and Allen virtually tied. After months of deadlock, most polls now show Kaine pulling ahead.

Kaine's lead comes despite of Republican presidential nominee Mitt Romney catching President Obama in Virginia. Another Rasmussen poll released Friday gave Romney a 1 percentage point lead, a statistical tie, and most other polls have indicated the race is tightening.

Kaine and Allen, both former governors, are well-known across the state, and it shows. Despite a heated and, at times, nasty campaign -- thanks in part to the addition of TV ads from outside groups -- the two candidate remain well liked, with 52 percent having a favorable opinion of Kaine and 50 percent liking Allen.

Republicans have accused pollsters of over-sampling Democrats in recent surveys and skewing results. But the party breakdown in the Rasmussen poll was 39 percent Democrat, 37 percent Republican and 24 percent other, similar to a Marist Poll released earlier this week.