Jordan Spieth picked up where he left off at the U.S. Open last week at Erin Hills ... with a birdie. In fact, Spieth birdied three of his first four holes and five of his first eight en route to a 7-under 63 in Round 1 of the Travelers Championship. 

He made eight birds in all and shot the lowest first round of his PGA Tour career. His parting gift after 18 holes? A one-stroke lead over Johnson Wagner and Brett Stegmaier.

"Got started nicely on the first," Spieth told Golf Channel after his round. "Saw a putt go in and that was big for me. Really haven't been seeing a lot of putts go in early in rounds to kind of feed off of them. Was able to do that today. Been striking the ball really well."

He has been doing that.

As he's done all season, Spieth was absolutely incisive with his approach shots. He finished in the top five in the field on Thursday in strokes gained on approach shots, which is basically where he's been all season (Spieth ranks No. 1 on the PGA Tour in strokes gained on approach shots). 

The scary part about Spieth's round for the rest of the field is that he didn't putt all that well (for him). He finished outside the top 25 in strokes gained putting. What's that going to look like on Sunday when he sees a few bombs go in? 

"I've heard unbelievable things about this tournament," Spieth said earlier this week. "I've watched it, I've watched the exciting last seven holes where anything can happen, and that's always fun for us. When you get opportunities to make birdies or even make a couple eagles on a nine-hole stretch with just hitting good, solid shots, you can come back from anywhere. It's also a lot more exciting because you have to play aggressive, and I think that that's something that if I'm forced to do, helps us."

Spieth was good but not great in his T35 appearance at Erin Hills last week. He often sits out weeks after majors (understandably so), but he noted to Golf Channel that he really gleaned some confidence from the 69 he shot in the final round at Erin. 

Clearly he's feeling himself going into the final three rounds at TPC at River Highlands. And after Jim Furyk shot 58 in the final round on this track last year, who knows what's possible? It's certainly a scoreable course, and it hasn't seen less than 10 under as the winning score since 1993. 

So Spieth still has a long way to go, and he has monumental chasers in Rory McIlroy (3 under) and Patrick Reed (3 under), but he's off to about as good a start as he could have hoped for.

"(We) thought this was a really good track for us," Spieth said to Golf Channel. "Sometimes you kind of fall into that. This year, made it a point to come here and see what it was about."

On Thursday anyway, it was all about Jordan Spieth.