Joaquin Niemann and Tom Lewis are tied for the one-shot lead at the halfway stage of the Rocket Mortgage Classic, where defending champion Bryson DeChambeau missed the cut.

Niemann and Lewis both carded three-under-par 69s in the second round of the PGA Tour tournament in Detroit on Friday.

Eyeing his second PGA Tour title and first since the 2019 Greenbrier Classic, Chilean golfer Niemann was bogey-free as he recorded three birdies to reach 10 under through 36 holes.

Englishman Lewis – a two-time European Tour champion but without success on the PGA circuit – was also flawless following three birdies without a dropped shot on day two.

Lewis is making his 45th career PGA Tour start. In his first 43 starts, he played the opening 36 holes in 134 or better once (134/2020 Shriners Hospital for Children Open). The 30-year-old has now done it in each of his last two starts – 134 at Travelers Championship and this week's Rocket Mortgage Classic.

Troy Merritt (68), Chris Kirk (68) and Max Homa (65) are a shot off the pace heading into the weekend, while overnight leader Davis Thompson (73) is among a group of players tied for sixth at eight under.

Former world number one Jason Day could only manage a second-round 73 as he fell to four under, six shots behind the leading pair – a stroke better off than Patrick Reed (72) and six-time major champion Phil Mickelson (72).

US PGA Championship winner Mickelson played the final two holes in one-under to finish three under, just a shot above the cut line.

"I am tired of trying to fight to make cuts. I want to get in contention, because that's what's so much fun, like it was at the PGA, just being in contention and having a chance," Mickelson said.

DeChambeau (71) was not so fortunate as the big-hitting American's title defence came to an end after just two rounds at one under.

Meanwhile, Masters champion Hideki Matsuyama was forced to withdraw before his second round after testing positive for coronavirus.