Tour Championship leaderboard
-20 V Hovland (Nor); -14 X Schauffele (US); -13 C Morikawa (US), K Bradley (US)
Viktor Hovland takes a six-stroke lead into Sunday's final round of the PGA Tour's season-ending Tour Championship after a four-under 66 in round three.
The Norwegian, who won last week's BMW Championship to move into second place in the FedEx Cup standings and start this week on eight under, is 20 under.
"I don't think I've ever played this well before," Hovland said.
Xander Schauffele shot a 68 to move to 14 under, one clear of fellow Americans Collin Morikawa and Keegan Bradley.
Rory McIlroy, who has been battling a back problem, is at nine under.
The Northern Irishman, who signed for a one-over 71, came from six shots back to beat Scottie Scheffler to last year's title.
World number one Scheffler, who started the tournament two clear of the field on 10 under par as leader of the FedEx standings, had four bogeys on Saturday before holing his solitary birdie on the last as he posted a 73 to drop nine shots off the pace on 11 under at East Lake in Atlanta.
Scheffler is tied with world number three Jon Rahm, who started the week at six under and had improved to 12 under after round two but shot a 71 in Saturday's third round.
A lightning storm suspended play for 75 minutes but it did not affect Hovland's progress and the world number five came out of the delay with birdies at the 12th and 13th holes to build a seven-shot advantage.
However, Olympic champion Schauffele birdied the 16th to give himself hope of emulating McIlroy's exploits from last year.
Morikawa, who did not drop a shot in his opening 40 holes, double-bogeyed the fifth and more shots went at the 10th and 11th holes as he posted a 73 to drop back to 13 under, while Bradley had four birdies and four bogeys in his level-par 70.
Sunday's winner from the 30-man field will take home $18m (£14.3m) from the $75m prize pot.
Follow the final round via live text commentary on the BBC Sport website from 18:30 BST.