Hideki Matsuyama leads the St. Louis by 5 shots. Jude Championship

MEMPHIS, Tenn. — Hideki Matsuyama felt his lower back begin to work. Suddenly, he decided to put a new putter in his bag for the start of the PGA Tour postseason. And now the Japanese star has a five-game lead going into the final round of the FedEx St. Jude Championship.

“I’m surprised,” Matsuyama said through his interpreter, smiling broadly as he added, “but I played well today.”

He played well enough for a second consecutive 6-under 64 that helped him clear a crowded field and put some distance between himself and Nick Dunlap.

Matsuyama quickly atoned for the early bogey by drilling a 3-wood over the water to 15 feet and making an eagle putt. He kept adding birds all day in hot weather, and no one could stay with him.

Denny McCarthy, who was tied on 36 holes with Matsuyama, added four bogeys to his card before registering his first birdie. Sam Burns had just five pars — and a broken driver — in his round of 70 to fall back. Scottie Scheffler lost the world by a few suspect chips and was seven shots behind with a 69.

“I felt like I stopped doing something, so I’m hoping to clean it up a little bit and give myself more opportunities,” Scheffler said.

Scheffler was 10-under 200 along with Burns, who hit his driver on the 9th and broke his head. He made double bogeys to go with five bogeys and seven birdies. It was quite a day.

Dunlap did his best to stay close and took three shots until one wild drive was too many. He went until he arrived on the 12th and removed the water and stayed on the other side, then he was able to save the level. But he hit the 13th again in the deep grass, couldn’t reach the green and took a bogey.

He shot a 66 and will be in the final group, extending his impressive run. Last year, he won the US Amateur at Cherry Hills. He won the American Express in January as a rookie, turned champion, and then won the Barracuda Championship last month.

“I’m supposed to be playing the US Am this week, and I just finished playing golf with Scottie. It was great,” Dunlap said.

Dunlap is among the top five players with multiple wins this year and has been on a long streak. He was No. 67 in the FedEx Cup because he was a rookie in his first PGA Tour title and did not score.

Even if he can’t catch Matsuyama, Dunlap has a chance to not only be in the top 50 heading into next week’s BMW Championship, but close out the Tour Championship’s top 30.

Matsuyama was 17-under 193 and on the verge of capturing his first FedEx Cup qualifying event.

But this postseason opener was about moving forward. The top 50, along with reaching the next playoff event outside of Denver, are guaranteed entry into all eight of the $20 million events next year.

Viktor Hovland, the defending FedEx Cup champion who started this postseason at No. 57, took a big step forward with 66. He was tied for third, six shots behind.

The ball is starting to behave the way I expected,” said Hovland. “The holes are a lot smaller than they used to be. They used to be out of the world, but now they’re manageable and I can make a good putt no matter what it is.”

Jordan Spieth’s season effectively ended when he made two bogeys in his round of 74, leaving him in 69th place against a 70-man field.

Will Zalatoris entered the postseason ranked No. 49 and shot a 67 on Saturday. He was tied for sixth and all but assured of staying well inside the top 50.

Among those on the bubble heading into Sunday are Justin Rose and Adam Scott. Rose is No. 55 in the FedEx Cup and was tied for ninth after 54 holes at TPC Southwind. He shot a 71 on Saturday after making a double bogey on the final hole. Scott is No. 46. He shot a 68 and looked to be inside the 50 going into the final day.

Others who appear to be in the top 50 include Harris English, who is still dealing with a bad back, and Phoenix Open winner Nick Taylor.

Rory McIlroy, who appeared to be playing tennis after his opening round in the heat on Thursday, had a bogey and two bogeys after just four holes on Saturday. He shot 74 and moved to the bottom of the pack. But he could afford a tough week, as he started at No.

Matsuyama has three top-10s in his last six events, including a bronze medal win at the Paris Olympics. Why do you change putters? He’s not really sure.

“I’ve had a putter for a long time, and I thought it might be a good week to start that putter,” Matsuyama said.

He leads the field in scoring statistics, averaging nearly seven shots against the field. He also has 19 birds and an eagle.