NEWRY — Seth Sweet of Madison played his best golf on the back nine Tuesday, overcoming a slow start to take the lead after the first round of the Maine Amateur at Sunday River.

A June graduate of Madison High, Sweet birdied four of his last nine holes to finish at 2-under 70 to start the three-day tournament.

The cut for the final day will be the low 40 and ties after today’s round.

The only player to go under par, Sweet built a two-stroke lead over Mike Doran of Portland, who shot a par 72. Mike O’Brien of Biddeford and Len Cole of Hampden are tied for third at 73.

Ryan Gay of Pittston, a three-time tournament champion, is in a five-way tie for fifth place at 74.

Jason Gall of Augusta and Matt Loubier of Winslow were among those who joined Gay at 74.

Mark Plummer of Augusta, a 13-time Maine Amateur champ, shot a 78 to tie for 20th place.

“It was a struggle. I didn’t play well today. I kind of hung in there,” said Gay, winner of the last two Maine Amateurs.

Sweet, 17, bogeyed the ninth hole to finish the front nine at 1 over but rallied on the back nine. He birdied the 10th, 13th, 15th and 16th holes. Those, combined with a bogey on 14, gave Sweet a 3 under on the back nine and a 2 under on the day.

The toughest hole of the day was the 443-yard, par-4 18th. A dogleg left with out of bounds on the right, the hole caused fits throughout the day. Seventy golfers shot a bogey or worse on No. 18, and three took a double- digit score on the hole.

Another tough hole was No. 14. There were just five birdies on the par 3, 213-yard hole. Gay had one of them. With the wind blowing in, Gay said he went to a 4-iron off the tee.

“I thought if I got it up into the wind, the wind would knock it down and leave me in front (of the pin), and it did,” Gay said.

Gay, who has won three of the last four Maine Amateurs, followed his birdie on the 14th with a bogey on No. 15.

Sitting 225 yards from the pin, he had a shot go into the woods to the right of the green.

“It was a stupid bogey,” Gay said.

Gay’s trouble aside, No. 15 proved to be the easiest hole of the day. A 518-yard, par-5, four players eagled it, and 37 others birdied the hole.