(Reuters) - Andrew Landry tired in sweltering weather but clung to a share of the lead after the third round at the John Deere Classic in Silvis, Illinois on Saturday.
Despite back-to-back bogeys at the 11th and 12th holes which he blamed on fatigue, Landry ended the day tied with fellow American Cameron Tringale at TPC Deere Run.
"I just got tired to be honest with you," co-leader Landry said after shooting four-under 67 on another day of low scoring.
"It was just really hot out there. My golf swing started feeling a little bit shaky, body was not really turning, was just kind of arming it and not really hitting solid shots."
Landry said he would take steps to feel stronger on Sunday when he will try to add to his one PGA Tour victory.
"I know I need to bring more food in the bag, drink more water," he said. "I'll eat some good food tomorrow and eat a good lunch."
While Landry battled fatigue, Tringale had to control his mind after bogeying the first hole. He was rewarded for his poise with a 65, joining Landry at 16-under 197.
Tringale, without a win in 261 career starts on the PGA Tour, gained some confidence with a tie for fifth in Detroit two weeks ago.
"I just learned that my good golf is good enough and when I play well I can play with the best," he said.
"I had a couple of down years and so to get in this position is exciting and re-proving to myself that I belong."
Overnight leader Jhonattan Vegas of Venezuela plunged eight shots behind with an error-strewn 76.
Haas, one stroke behind after matching the day's best score of 64, has the best pedigree among those on the leaderboard, with six career victories.
He has not won since 2015, however, and knows he must play with composure on Sunday to end his four-year drought.
"Good play, it's easy to be positive, but all the best players, none of them seem to let things bother them," he said.
"It helps that they're really, really good but at the same time I've got to somewhat go into tomorrow thinking I can win, approach every shot like I can pull it off and then see what happens."
More than victory is at stake on Sunday, with the winner likely to secure the final spot in next week's British Open at Royal Portrush.
Nobody in the top eight is currently exempt for the final major of the year.
(Reporting by Andrew Both in Cary, North Carolina; Editing by Ian Ransom)