Dustin Johnson makes tidy return from back injury

-Johnson four shots off pace

-Leader Molinari chips in twice

World number one Dustin Johnson declared himself ready to challenge for victory after a tidy return to competition left him four strokes behind first-round leader Francesco Molinari at the Wells Fargo Championship on Thursday.

Twenty-nine days after slipping down stairs and badly bruising his back on the eve of the U.S. Masters, Johnson reported no ill-effects after his morning round at Eagle Point.

He carded a two-under-par 70, while Italian Molinari chipped-in twice to lead on 66, one stroke ahead of four players including Swede Alex Noren.

"I felt good physically, no issues," world number one Johnson told reporters. "I just need to get some more rounds in, get some more reps, but I feel like the golf swing's in good shape.

"I hit the ball great. If I hit it like I did today (over) the next few days, I'll be right there on Sunday."

The only top-10 player in the field, Johnson attracted a huge gallery in what almost counts as a home tournament, taking place as it does not far from where he grew up across the border in South Carolina.

Johnson was perhaps more satisfied with his performance than his score in his quest to become the first player since Tiger Woods in 2007-08 to notch four consecutive victories on the PGA Tour.

"Since I hadn't played in so long I'm happy with the way I played," he said. "I didn't score that great, didn't hole many putts. I felt like I hit good putts, just nothing was going in. All in all I'm very pleased with the day."

Many players approached the first round apprehensively on a course few had played before this week, but low scores were plentiful after the greens were watered overnight, allowing for attacking approach shots.

Solid Round

"It's a great track, not the longest, but especially in the breeze, you need to hit the ball in the right spot on the greens," said leader Molinari.

"Just a good, solid round. I hit a lot of good shots, gave myself a lot of chances. I missed some makeable ones but made a couple from off the green, so great day."

His first hole-out came at the fifth, from 25 yards, while he also chipped in from 25 feet at the last.

Molinari is seeking his first U.S. PGA Tour victory, after winning four times on the European Tour, including the 2010 WGC-HSBC Champions in Shanghai.

Noren played with the precision befitting a world number 12, before saying he wants to play more on the PGA Tour, without abandoning Europe.

"I've got a little kid at home," he said. "They like it in Sweden and we'll see how it goes."