Who is Jordan Spieth's caddie? Meet Michael Greller

Behind every great player is a great caddie, and Jordan Spieth is no exception. 

Spieth and his caddie, Michael Greller, share a bond that goes beyond the golf course. 

Their relationship, one of the closest on the PGA Tour, was forged when Spieth was a young amateur. 

The pair have worked together since 2011, during which time they have amassed 13 career wins, including three major championships. 

Before he became Spieth's caddie, Greller was a high school maths teacher, living and working in Seattle.

He worked part-time as a caddie to earn some extra cash and quickly earned a good reputation on the circuit. In 2010, he caddied for Justin Thomas at the US Amateur Championship, and a year later, when the US Junior Amateur rolled into town, a young Spieth requested his services. 

Spieth went on to win the tournament that week and called upon Greller's services once more when he made the field for the US Open in 2012 as the No.1 amateur in the world. 

Upon turning professional in 2012, Spieth enjoyed immediate success, becoming the first player since 1931 to win a PGA Tour event as a teenager when he won the John Deere Classic in 2013, aged just 19. 

Initially, Greller had only planned to take one year off from his job as a teacher to caddie for Spieth. However, after witnessing Spieth's early success and realising the potential of their partnership, he made the life-changing decision to make the position permanent. 

In the 2014-15 season, Spieth had a career year, winning both The Master and US Open. He also finished T4 at The Open and came second at the US PGA. 

That same year, he also won the Tour Championship, Valspar and John Deere Classic for a second time. 

In 2016, the pair won twice more on the PGA Tour, with victories at the Dean & Deluca Invitational and the Hyundai Tournament of Champions. 

While the pair quickly achieved success, they also suffered their fair share of heartbreak, most notably at the 2016 Masters, when Spieth looked nailed on to win the green jacket for a second time, only to be cut down when he dropped five shots on the famously tricky 12th hole at Augusta National. 

Despite the horrific collapse, Spieth and Greller went on to claim perhaps their most famous victory in 2017, when the pair got their hands on the Claret Jug for the first time at Royal Birkdale.

Going toe-to-toe with Matt Kuchar down the final stretch, Spieth produced an inspired stretch of golf, which he puts down to a pep talk he received from his bag man. 

Greller notoriously told Spieth that he was in the same calibre of athlete as basketball legend Michael Jordan and 23 time Olympic gold medallist Michael Phelps.

Upon hearing the encouragement, Spieth went on to win The Open, eventually winning by three shots. 

One of the PGA Tour's most instantly recognisable duos, Spieth and Greller are renowned for their pre-shot routines. Greller is often considered the team's voice of reason. 

Greller grew up in Michigan and had two siblings. He married his wife Ellie at Chambers Bay, the same course where Spieth won his first US Open title in 2015.