Zach Johnson uses Matt Kuchar's wife as emergency caddie in Mexico

Zach Johnson required an emergency caddie on Thursday for the back nine of his opening round at the Mayakoba Golf Classic because his regular looper, Damon Green, was struggling with the Mexican heat.

Luckily, Johnson was playing alongside good friend Matt Kuchar, whose wife, Sybi, was following the group and stepped in on short notice.

"I knew Sybi was in the crowd, I knew she'd caddied for me before, she’s friendly with Zach Johnson," Kuchar said after his round, according to Dylan Dethier of Golf.com.

"I figured she'd be a good one to handle Zach and Zach would definitely go easy on her. She knows the deal of keeping up and staying out of the way and so I knew she could handle it, she'd be good to fill in."

Temperatures at El Camaleon Golf Club touched 90 degrees with no wind and high humidity on Thursday, according to Dethier.

Johnson was 2-over at the time Green stepped away but managed to battle back to even par with Sybi on the bag.

Meanwhile, Kuchar fired a 7-under 64 to share the early clubhouse lead. It was his lowest worldwide round since February, according to Justin Ray of Golf Channel.