The Bolton-born boxer conceded that he could struggle against the 33-year-old American, who has a record of 41 wins from 49 contests.
"He's been in some big, big fights and is very hard to knock out,” Khan said.
"Sometimes it's risky the way I fight, but that's what makes me special. People want to watch me because they know I take risks.
"He still has the speed, still has the power and knows how to use them. Experience has made him trickier now."
Both fighters weighed in on the 140lbs limit ahead of the contest, which is due to start at around 4am tomorrow morning UK time.