Sanders' lag behind Clinton is in the single digits, 46 percent to 39 percent, a poll by Morning Consult said Friday. It is "the largest percentage the Vermont independent has ever notched in a Morning Consult survey."
The poll showed the U.S. senator from Vermont leads 55 percent to the former secretary of state's 36 percent among voters 18- to 29-years-old, while Clinton is performing better among those over age 65. Sanders is leading among Independents, while Clinton is leading among Democrats.
Sanders was a longtime Independent, but switched his party affiliation to Democrat in November on the campaign trail.
"More Democrats now say they see Sanders favorably, 78 percent, than those who say the same of Clinton, 75 percent. Until now, Clinton has enjoyed an edge in favorable ratings among her party's voters," the poll said.
The poll found Sanders still needs to make inroads among non-white voters in states where black and Hispanic voters dominate. Clinton leads 63 percent to 26 percent among black voters and 52 percent to 44 percent among Hispanics.
The poll also found Republican nomination hopeful Donald Trump is soaring ahead of other Republican candidates, with 44 percent to second-place Sen. Ted Cruz's 17 percent. Florida Sen. Marco Rubio and retired neurosurgeon Ben Carson both take 10 percent. Former Florida Gov. Jeb Bush takes 8 percent while Ohio Gov. John Kasich wins 4 percent.
The Morning Consult survey polled 1,600 registered voters Wednesday and Thursday, with a margin of error of 2 percentage points. Subsamples of 811 Democrats and Democratic-leaning voters and 710 Republicans and Republican-leaning voters carry margins of error of 3.4 percentage points and 3.7 percentage points, respectively.