Carlsson and MacLaren are at ten under par, two shots clear of the trio of Christine Wolf, Karolin Lampert and overnight leader, Valdis Jonsdottir.
MacLaren made her intentions clear early today when she slotted an eagle putt on the par five third to jump to eight under.
Despite a bogey on the 4th, she bounced back with back to back birdies on the 5th and 6th to reach nine under par.
By the time she turned for home, she was battling for the lead with overnight leader Valdis Jonsdottir and the Swede Carlsson.
Another birdie got Maclaren to ten under and in a share of the lead for a period before a bogey at the 14th saw her fall back to nine under.
When MacLaren birdied the testing par five 16th, which had proved her nemesis during the first two rounds, she was sitting on top of the leaderboard alone.
The Englishwoman finished her day with a couple of solid pars on 17 and 18 to ensure her place in the final group tomorrow.
Maclaren was pleased with her effort post round, despite claiming it was ‘a little bit up and down’
“It was good out there today,“ she said.
“It was a little bit of a different round to the past two days and felt like I had a bit more up and down in it.
“I made an eagle early on, which was a nice little kick start to my round.
In an ominous sign for the field, MacLaren said had it not been for her misbehaving putter, the score could have been better.
“I didn’t hole as many putts as I would have liked, but I rolled in a couple from long range, so it probably balanced itself out.”
Asked about the added pressure of being the defending champion and also being in the final group on Sunday, Maclaren wasn’t fazed.
“I think that anybody not wanting to be in the lead would be crazy.
“It’s sometimes nice to come from a few shots behind because there’s less pressure. But if you’re on the lowest score, that’s where you want to be at the end of the week.”
“I can’t complain. I feel like I’ve left shots out there, but I’m still standing here at the top of the leaderboard, so that tells me a lot about where my game is right now.”
Sweden’s Lynn Carlsson certainly proved the pressure of playing in the final group on Saturday hadn’t affected her in any way when she carded a 67 to match MacLaren.
Coming to the last just a shot behind, the young Swede played the shot of the tournament, rifling her 8 iron approach from 125 metres to tap-in range and grandstand finish in front of the large gallery.
“I enjoyed today and played solid," Carlsson said.
“I hit a lot of good approach shots and had a few easy birdies, so it was nice,” the Swede said.
Earlier, the 24-year-old had caught fire in the middle of the round, with birdies on the 6th, 7th, 9th and 10th to be the first player to reach ten under par.
“I fired in the middle of the round with four birdies, It was similar to yesterday,”
“I guess I like those holes," she grinned.
Carlsson isn’t phased by the thought of going head-to-head with MacLaren, the defending champ in tomorrow’s final round.
“It’s a new day tomorrow, so we’ll see what happens then, but obviously it’s a good feeling.
“It’s always nice to be in contention, so it will be a good day.
“I haven’t played with Meghan before so I’m looking forward to that,” she smiled
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