Koepka eyeing Johnson in pursuit of FedEx Cup and top ranking

Brooks Koepka is eyeing Dustin Johnson's top ranking and FedEx Cup glory following the opening round of The Northern Trust.

Dustin Johnson is firmly in the sights of three-time major champion Brooks Koepka, who wants to dethrone the world number one and win the FedEx Cup.

US PGA Championship winner Koepka is second in the golf rankings, while the American sits third behind leader Johnson in the FedEx Cup standings.

Despite missing over four months this year due to a wrist injury, Koepka is contention to claim the top ranking and FedEx Cup, with Johnson standing in the way of both accomplishments.

READ: Johnson, Koepka lurking as four share Northern Trust lead

Koepka and Johnson have become good friends off the course, but the former would not feel too bad about knocking his countryman off his perch.

Speaking after shooting a four-under-par 67 to be a stroke off the pace alongside Johnson at The Northern Trust on Thursday – the opening FedEx Cup play-off event – Koepka said: "I'd love to knock him off, and I'm sure he'd love to keep me where I'm at."

"You know, it's fun. It's actually been really good for the both of us. Kind of in the gym, obviously working a little bit harder, trying to out-train him and he's trying to out-train me, and on the golf course, I'm trying to out-perform him and he's trying to do the same thing. It's been good for the both of us, so hopefully it continues for the next however many years."

Having won three of the last six major championships, Koepka seemingly has an eye for the big events. Now, he is trying to translate that success to regular-tournament wins.

"I'm just trying to make sure — I think maybe over the last two years, my routine is starting to really evolve off the golf course, so I'm trying to bring that and make sure it's here each and every week," he said.

"You know, I've played pretty well in a lot of PGA Tour events. I think we've had, what, seven second-place finishes in the last two years. Sometimes, it goes your way. Sometimes, it doesn't. So, it's not like I'm not in the position a lot. It just hasn't gone my way sometimes."

By this time in the season, Koepka is just trying to make sure his mind and body remain fresh and ready to compete. "[I] feel good. Took last week off. Didn't hit a ball till Tuesday, but it was nice to be mentally fresh coming in. I don't need to play every week, every day, to stay fresh," Koepka said.

"I'd rather be mentally fresh than be grinding away. I feel good riding the momentum from St Louis, which is nice, and any time you come back, the next time you tee it up, you're very focused and ready to win. It just makes you that more hungry."