Phil Mickelson and Henrik Stenson are positioned for an intense battle during Sunday's final round of the British Open.
The aging stars separated themselves from the rest of the pack in Round 3. Mickelson is trying to become the second oldest player to win the Open. He beat Stenson in the 2013 Open.
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Sunday's final round begins about 4 a.m. ET. Mickelson and Stenson, the round's final pair, will tee off about 10 a.m. ET.
Conditions have been difficult since the benign opening round, but Mickelson and Stenson remained steady. Both players putted well and placing their tee shots in good spots to attack these small greens.
Sunday should be classic match-play-like battle.
Here are the contenders heading into the final round and what they need to do to win:
Henrik Stenson (-12): One of the best active players without a major championship, Stenson, 40, has another chance. With a large cushion above the field, other than Mickelson, he can treat the final round like a singles pairing on the final day of the Ryder Cup. As long as he keeps his composure on the greens he should be able to give Mickelson a tough fight.
Phil Mickelson (-11): After two rounds of near flawless golf, Lefty hit uncharacteristic shots in Round 3. Mickelson, 46, is in great shape to win his sixth major and second British Open. All he has to do is outlast the man he edged in 2013.
"Old" Tom Morris is the oldest winner. He was 46 when he won in 1867, just days older than Mickelson is now.
Bill Haas (-6): After Saturday's excellent 2-under 69, Haas is in the best position should the leaders falter. He might not have a flashy game or style, but Haas has won the FedEx Cup and been a prominent member of the PGA Tour for close to a decade. He must be aggressive in Round 4.
Andrew Johnston (-5): Nicknamed "Beef," Johnston is a portly and enigmatic fan favorite who has had the crowd on his side. Playing in just his third major championship, this Englishman looked solid. Starting so far back, he must relax and try to make birdies, hoping the leaders fall back to him.
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A word about the weather: After morning showers, the final round should play out under partly clouds skies with temperatures from the mid-50s to upper 60s.