SANFORD – Ricky Jones of Thomaston fell behind early but caught and defeated Keith Patterson of Biddeford on Thursday to keep alive his chances of defending his Maine Amateur Golf Championship crown.

Jones finally pulled ahead on the 15th hole at the Sanford Country Club and held that margin the rest of the way to defeat Patterson 1 up in their afternoon quarterfinal match.

“The matches keep getting harder and harder,” said Jones after winning his second match of the day.

“Actually, every match has been close,” said Jones after further reflection. Jones had defeated Nate Nealey of Gorham 3 and 2 Thursday morning to advance to the quarterfinals.

In the other quarterfinals, Cash Wiseman, playing out of Sable Oaks Golf Club in South Portland, rallied to top J.J. Frost of Brewer 1 up; Marc Siewertsen of Westbrook birdied three of the first four holes and downed Jeff Wass of Rockland 5 and 4; and Ben Daughan of York stopped Jason Gall of Cumberland 2 and 1.

In Friday’s semifinals, Jones will face Siewertsen at 7:30 a.m. and Wiseman will take on Daughan at 7:45 a.m. The two winners will play for the title at approximately 12:30 p.m.

Jones, who won the Whited Ford Paul Bunyan Amateur Golf Tournament in June, struggled with his short game early in the afternoon match, while Patterson quickly started draining putts.

On the first hole, a short par 4 as the Maine State Golf Association has reversed the nines for this event, Patterson stuck his approach shot about 10 feet above the pin. Jones, meanwhile, with a shorter pitch, left his approach on the front of the green well below the pin.

Jones’ first putt came up several feet short, but Patterson’s delicately tapped putt fell in for birdie.

The second hole was almost a replay of the first as Patterson reached the front of the putting surface, but Jones came up short of it. He chipped up close, but Patterson dropped a 20-footer for birdie and a 2 up lead.

“I have a hard time hitting uphill when I can’t see the pin or the hole,” said Jones.

The two matched scores over the next four holes with Jones missing a couple of birdie putts and Patterson making par-savers to maintain his lead.

“I needed to get off to a good start against him,” said Patterson. “He can get it going low any time.”

Jones won Nos. 7 and 8 to even the match again, but missed a 3-foot putt on No. 9, putting Patterson back in front.

“That was the same putt I had in the morning,” Jones said. “I knew how it broke; I just pulled it.”

Jones pulled even again on 12 when Patterson suffered a rare three-putt.

“I putted well all day,” said Patterson. “It had to run out eventually, I guess.”

Jones took the lead when Patterson hit his tee shot on 15 to the right, which he had been doing a lot, and made bogey to Jones’ par.

Jones almost doubled his lead on 16, but his putt rolled around the cup and stayed out. On 17, he lipped out a 6-foot birdie putt that would have ended the match.

“I just couldn’t make anything,” said Jones.

Patterson sliced his tee shot on 18 and had to punch out from the edge of the trees.

Jones three-putted for bogey, but it was good enough to win.

“Everyone is so even out there that it comes down to a [late] charge or don’t make mistakes,” said Jones.

Frost traded wins with Wiseman on the first two holes before taking a 2-up lead by making birdies on the two front-side par 3s.

Frost still held a 1-up lead after 16, but his chip for birdie on 17 stopped on the edge of the cup. Wiseman sank his 8-foot birdie putt to square the match going into the last hole.

“Another half a revolution and he needs to make his just to stay in the match,” said Frost, the Maine Amateur runner-up two years ago.

Frost’s tee shot on 18 got away from him and Wiseman made him pay by putting his approach shot easily on the green. Frost came up 30 yards short on his second shot, then came up short again on his pitch.

Frost’s chip for par rolled past the cup, and Wiseman got the win.

“We both played good today,” said Frost. “It just came down to one bad swing.”

Siewertsen, a former pro who has regained his amateur status, played like a pro in his two matches Friday. He was 3 under par over the 14 holes of his morning victory over Gary Manoogian of Westbrook and 4 under par over the same 14 holes against Wass in the afternoon.

“When you play a quality player and get behind, you can’t think they’re going to make many mistakes and let you back in,” said Wass.

Siewertsen birdied Nos. 1, 3, and 4 to go 3 up against Wass and kept pushing to build the lead.

“Today was the first day standing over the ball that it felt good,” said Siewertsen.