Morikawa in four-way tie for lead as Scheffler lurks

Collin Morikawa is showing further signs he's getting back to the form that made him a two-time major champion, shooting a five-under 66 to share the halfway lead at the PGA Tour's RBC Heritage.

Masters champion Scottie Scheffler's form never seems to change. Even after an emotionally taxing victory at Augusta National, a quick trip home to Dallas and only nine holes of practice, the world's No.1 player is right in the mix again.

It's crowded at the top after two days of warm, ideal conditions for scoring at Harbour Town, and this $US20 million signature event is wide open going into the weekend.

Morikawa had a four-way share of the lead with Tom Hoge (64), J.T. Poston (68) and Sepp Straka, who recovered from an opening drive that plunked a spectator in the head and led to a double bogey.

Straka saw blood but settled down after hearing the spectator was going to be fine, then put together eight birdies for a 65.

The leaders were at 11-under 131, one shot ahead of a group that features Ludvig Aberg, the Masters runner-up who is starting to get anointed the biggest challenger to Scheffler.

Scheffler, whose Masters win was his third title in his last four starts, didn't look as though he did anything special, the very trait that makes him so good.

He was bogey-free, picked up birdies on the par 5s on the front nine and then ran off three birdies in a four-hole stretch on the back for a 65 to be three shots back.

Australia's Jason Day was hurt by two late bogeys as he shot a 69 to be tied 23rd, six shots from the lead.

Morikawa has been searching for the key to that repeatable swing that led to a PGA Championship title in 2020 and the British Open a year later. He won last fall in Japan, but has been lacking the trust in whatever fix he keeps making.

But he found something at Augusta National last week - he was among those tied for the lead on Sunday until a pair of double bogeys around the turn - and kept hitting the sweet spot during practice and the opening two rounds of the RBC Heritage.

"Still have a lot of trust in the swing," he said. "Whether it went right or wrong, I was able to kind of accept the fact and move on. Two or three months ago -- or even two weeks ago -- if I saw a couple of bad shots it was like, 'What do I fix? What do I try?'

"I kind of roughly know where the ball is going, and even when I'm missing it, still everything is a little bit tighter," he said. "That's all you can ask for."