Matsuyama was in the process of shooting a six-under par back nine that resulted in a tournament equalling low of 65. The 20-year-old from Tohoku Fukushi University - who narrowly missed an 2.4m birdie putt on the 18th - has become something of a Saturday specialist as he also shot 65 on the Saturday in last year's competition. He shot a third round 67 at this year's Masters Tournament on his way to winning the Silver Cup for low amateur.
Campbell said: "I saw a leader board on the par-five 16th, but I just ignored it, I don't like to look at the leader board while I am playing.
"I just like to play my own game and focus on that, I don't want to pay attention to what anyone else is doing on the course. I try to shoot the best that I can, if it is good enough it is good enough, and if it's not then it's not.
"I finished birdie, par, birdie, so that wasn't too bad. I had a disappointing double when I was at 14 under so it would have been nice to keep my low round going, but we'll see what happens tomorrow."
Campbell, who had surgery on his foot seven weeks ago, believed he needed to get to 20 under par to win the tournament.
He will not be intimidated playing with Matsuyama in the final group.
"He is just another player in the tournament", he said.
"I just want to keep going out there and do what I've been doing for the last couple of days."
Matsuyama, 19, was low key about his performance, which included birdies at holes 3, 6, 11, 13, 14, 16 and 17, claiming to be disappointed.
"I think I was lucky, I don't think I played as well as my first round," he said referring to the 67 he shot on Thursday. "In fact I don't think I played as well as I'd liked to today. I am hoping to manage my play better for [today]."
One thing he was clear on was what will be motivating him during today's final round, which gets under way with a two tee start at 8am.
"Last year I did not know much of the pressure because I have never been to an Asian Amateur Championship, there was no pressure at all," said Matsuyama, who has a college teammate caddying for him this week.
"However, this year, I want to overcome that because I really want to go back to Augusta really bad. There were too many emotions going around in today's play but I will have to manage that better tomorrow - I will try to enjoy the pressure tomorrow.
"I have nothing special strategy- wise, I think all the players will get a lot of pressure coming into [today] but this is normal. For my own strategy, I like to my focus on my own game."
Campbell and Matsuyama, who will start from the 1st in the final group at 9.40am, may not have things all their own way. It is by no means a two-horse race as Australia's Cameron Smith shot an impressive 69 on his own to finish on 10-under par to stay in touch.
First round leader Lee Soo-min, of South Korea, finished the day in fourth on nine-under par with Vaughan McCall of New Zealand and Masamichi Ito of Japan sharing fifth place a further shot back.
McCall, from the Gore Golf Club, climbed 10 places into fifth after a five under par 67 on moving day in an impressive display from the rookie at this level.
Royal Auckland's Ryan Fox is in a share of seventh place after a two under par 70 in the third round and Hamilton's Mathew Perry drops to tied ninth after an even par 72.
Sam An dropped one place to a share of 28th after a two under par 70.
