K.J. Choi posted a second successive three under par round of 69 to open a two-stroke lead at The Senior Open Presented by Rolex.
The morning starters were met with strong winds at Carnoustie Golf Links but the South Korean remained patient as he reached six under par, two clear of overnight leader Stephen Ames who posted a level par round of 72 on the second day.
The 54-year-old, who spent 40 weeks inside the top ten on the Official World Golf Ranking, mixed one bogey with two birdies on the front nine, before going birdie-eagle from the 11th to surge into the lead.
The 2011 PLAYERS winner bogeyed the par three 13th but got one back with a birdie at the par four 15th, before bogeying the last for the second day in succession to settle for six under after 36 holes.
"It’s still a tough course, every tee shot and second shot," said Choi. "My home in Dallas in the States, it’s windy, very strong. I can practice my iron play, low ball, curving ball, right-to-left kind is a tough shot.
"Today's iron shots were better than yesterday and still inside six, seven foot, the putter, reading is very difficult. Couple of mistakes on some shots and couple of mistakes with the putter but still scored the same as yesterday."
Canadian Ames remained in the hunt for his maiden Senior Major by posting a birdie and a bogey apiece to sit second on four under, one clear of Australia’s Richard Green and Irishman Pádraig Harrington, who made four birdies in a round of 70.
"I think it was a bit tougher today, this morning, than it was yesterday afternoon," said Ames. "A lot more blustery. It was more going for the middle of the greens, 25-, 30-footers. It was tough to make birdies from there. They did a good job of tucking the pins. It was obviously a bit more difficult to get birdies out there."
Harrington is aiming to become the fifth player to complete the prestigious double of The Open and The Senior Open, and he is handily placed ahead of the weekend.
"Three behind going into the weekend. You know, still in there," he said. "That's where you want to be. And you know, I was just saying to Ronan, we've only played 36 holes. Feels like we've done 72 at this stage. Been a tough 36 holes with that weather and wind and you've got to all be on, and I'm sure it's going to be another 36 of tough mental fortitude to come."
Spaniard Miguel Angel Martin is fifth on two under after matching his first round effort, while India’s Arjun Atwal earned a share of sixth place with the low round of the day, a four under 68 which included five birdies in six holes from the tenth.
Atwal is joined on one under by former champions Paul Broadhurst and Darren Clarke, among others.
