World No.8 Jason Day is keeping the leaders honest after applying some heat in the final round of the US PGA Tour Tournament of Champions, rocketing into the top three midway through the round.

Day has nine birdies in his last 11 holes to be 18 under for the tournament with just three holes to play, now third but two shots behind American leader Jimmy Walker.

Walker has moved to 20 under for the week through eight holes of his final round, one shot clear of playing partner Hideki Matsuyama.

Day opened with four pars on Sunday before catching fire.

He slotted a short birdie putt home on the fifth, dropped a 20 footer into the cup on the sixth, doubled it with a 40-foot effort on the seventh before coaxing in another birdie on eight to announce himself a potential contender.

A missed opportunity to birdie the par five ninth followed, but not to be deterred, Day wedged to three feet on the 10th and then put away a seven-foot chance on the 11th.

A par on 12 was followed up by two more approaches inside seven feet on 13 and 14 and then a 14-footer found the cup on the 15th pushing him within striking distance of a course record.

Matt Jones is the next best Australian at 13 under in a tie for 13th while Steven Bowditch (-10), John Senden (-8) and Geoff Ogilvy (-8) are towards the back end of the 34-man winners only field.