The faultless seven-birdie round over the tricky Marquess course lifted the Scot into joint fourth place at halfway on nine under par, just two shots behind South Korean leader, Mirim Lee.
Matthew famously won this title – the first and only Scot to claim a women’s major – just 11 weeks after giving birth to her second daughter, Sophie, at Royal Lytham and St Annes in 2009.
And, if she could go on and win the title for a second time tomorrow, it would add to a July that, even by her standards, has been quite remarkable for the 46-year-old from North Berwick.
She has achieved two career landmarks this month, gaining a place in Team GB for the forthcoming Olympics and being picked by Annika Sorenstam as a vice-captain for next year’s Solheim Cup.
As for yesterday’s round, even the ever modest Matthew deemed it was one of her most special. Four birdies on the front nine, including her longest putt of the day from 25 feet at the seventh, and three on the inward half made it a day to remember.
“It was definitely one of my best rounds ever,” she assessed. “I hit just one awful shot [a hooked tee shot at the 16th] but then hit a near perfect four iron and almost made birdie.
“The crowd was great today and if I can get myself into position to have a chance on Sunday I’m sure it will be even better. I’ve already had two huge achievements this month. When I was growing up, I couldn’t even dream of getting to play in the Olympics and the Solheim vice-captaincy is another huge honour.”
Mind you, all the signs are that Matthew will still be as much of an asset on the course as off it for Team Europe at Des Moines in Iowa, and she certainly hasn’t ruled out making her ninth appearance next year.
“Annika and I discussed it and it is certainly a possibility that I could be a playing vice-captain,” she said. Then, of course, the Solheim is at Gleneagles in 2019 – and surely Matthew is being lined up as captain?
But back to the present. This weekend is all about trying to win her 12th professional title and a second major, and she is being helped along the way by husband Graeme.
Her caddie for most of her career, his travels have been curtailed since their two daughters – Katie is nine – started school. This is just his third stint on the bag this year.
“It’s nice to have him caddying, and just nice to have him here this week,” Matthew added. “It’s so long since we travelled regularly together.”
Graeme will also be accompanying her to Rio for the Olympics, and both will be staying in the village.
Lee, the first round leader on 62, had a much tamer second-round 71 but it was still good enough to lead on 11 under, one ahead of China’s Shanshan Feng (68) and Thailand’s Ariya Jutanugarn (69). Matthew was alongside another Korean, Ha-Na Jang.
But, while Matthew continues to fly the Saltire with pride, she is the only Scot in action this weekend. Kylie Walker and Pamela Pretswell both missed the cut that fell on one over. New Zealand’s world No 1 Lydia Ko made it with just a shot to spare after two late birdies in a round of 70.