The North Berwick woman covered the last six holes on the South Course at NCR Country Club in Kettering in two-under-par as she signed off with a level-73 on a day when no one broke par.
The splendid effort secured Matthew a share of third spot as she finished on one-under, two behind Jill McGill as the American landed the over-50s title in her first year of eligibility.
Matthew, who had geared her season for the USGA event, picked up a cheque for just under $59,000 as she shared the honour of being the top European along with former winner Helen Alfredsson from Sweden.
The duo finished two shots ahead of two other former champions - Alfredsson’s compatriot Annika Sorenstam and England’s Laura Davies.
McGill, who won by a shot from fellow American Leta Lindley added this title to wins in the 1993 US Women’s Amateur and the 1994 US Women’s Amateur Public Links.
She joins Arnold Palmer, Jack Nicklaus, Tiger Woods, JoAnne Carner and Carol Semple Thompson as the only players to win three different USGA championships.
“That sounds amazing,” McGill said when introduced as the champion. “I love the USGA. I've loved it ever since I got spanked in my very first Junior Girls by Brandie Burton. That was a welcome to competitive golf.”
The triumph also earned her an exemption into next year’s US Women’s Open at Pebble Beach.