The Englishman took advantage of the good scoring conditions to card a seven under 63 around TPC River Highlands in the third round on Saturday. That moved him to 16 under for the tournament, three strokes ahead of US Ryder Cup Captain Keegan Bradley and Russell Henley.
Fleetwood was flawless, never missing a fairway and rolling in five birdies and an eagle on the par five 13th. He has dropped just one shot all week in Connecticut. He has seven wins on the DP World Tour and two runners-up finishes in the majors, but Fleetwood is still hunting a maiden PGA Tour title.
"I'm on top of a lot of stat lines for people that haven't won on the PGA Tour, so to always be a No. 1 at something is always nice," the 34-year-old said with a laugh.
"Yeah, of course I would love to win on the PGA Tour. I think it's like an element of your career that everybody wants, and I of course want it. I haven't, this year especially, I don't feel like I've given myself ... I've given myself a back end chance a couple of times this year, but I've not been in contention. So this is like my first real chance, so I'm really excited about that and looking forward to it."
Meanwhile, Bradley won the Travelers two years ago but admits its a steep mountain to climb on Sunday.
"Oh, man, you're going to have to shoot something at least in the mid-60s, probably where I am, probably lower," said the American.
"But it's doable out here. When you play a course where you've got to make birdies it brings a different challenge. You can't have a stretch of one over par for seven holes, or you lose a million shots. So in some aspects it's difficult just like a hard course would be."
Further down the leaderboard, Scheffler had a 29th birthday to forget. The world number one started with a triple bogey and never quite recovered, posting a 72. He joins Rory McIlroy on seven under, nine shots behind.