PGA Tour rookie Harry Hall has maintained the solo lead through 36 holes at the Charles Schwab Challenge after piecing together another impressive round.

After opening with an 8-under 62, Hall had four consecutive birdies midway through Friday's second-round 66 to be at 12-under for the tournament.

Hall's birdie streak ended with a bogey at the par-4 third, his 12th of the day, when he missed the fairway and then came up short of the green before a two-putt from 9 feet.

In the final group of the day, Hall hit his tee shot at No.8 into the sand in front of the green.

The Englishman failed to get the ball out of the deep bunker on his first attempt, but saved par by popping it out on the next try to the edge of the green and watching it roll into the cup.

It was a spectacular save for a three-stroke lead over Harris English, who quipped to his caddie no one was going to beat him at Colonial's par-3 eighth.

It proved true after he followed his birdie in the opening round with a hole-in-one. English's ace at the 170-yard eighth was part of his bogey-free 66.

"Hard 9 ... pushed it about 4 or 5 yards right of where I was aiming, but it's a good thing that hole got in the way," English said. "Just one of those shots where I struck it pure, right at the flag."

His third hole-in-one on the PGA Tour was the first at Colonial's No.8 hole since Jim Furyk in 2011.

English was a stroke ahead of Emiliano Grillo, who shot a round-best 65 to get to 8 under. Adam Schnek (67), Byeong Hun An (66) and Robby Shelton (67) were tied for fourth.

Scottie Scheffler, the world's No.1 player and Colonial runner-up in a playoff last year, had his second consecutive round of 67 and was tied for seventh at 6-under 134.

Justin Rose, whose 11 PGA Tour wins include Colonial five years ago, was tied for ninth at 5 under after a bogey-free 66.

Jordan Spieth, still dealing with a sore left wrist, shot 72 both days to miss the cut. The 11th-ranked player had three bogeys and a birdie over his last four holes.

Another who failed to make the weekend was Cam Davis.

The Australian opened with 68 but missed the one-over cut by one after a disappointing 74.

Davis's horror round included a double bogey on the ninth and four consecutive dropped shots beginning on the 11th. 

Min Woo Lee followed his 67 with a 71 to be tied 28th at two under, while Aaron Baddeley at one over (70, 71) is the only other remaining Australian in the field.

Michael Block, the 46-year-old club pro from California who became a sensation for everyday golfers by tying for 15th Sunday in the PGA Championship at Oak Hill, was last in the 120-player Colonial field at 15-over 155.

After his opening 81, he was seven strokes better with a 74 that included back-to-back birdies midway through the round.

It was an exhausting span for Block, who hit only 11 of 28 fairways over two rounds, but he still mingled with fans signing autographs and taking photos hours after his final putt before flying home.