ATLANTA (AFP) — Viktor Hovland shrugged off severe heat and a storm delay to seize a six-stroke lead after Saturday's third round of the US PGA Tour's season-ending Tour Championship.

The 25-year-old Norwegian fired a four-under par 66 to stand on 20-under after 54 holes at East Lake in Atlanta with American Xander Schauffele a distant second.

Temperatures soared near 100 degrees (37.7 Celsuis) before a late-round storm stoppage, but neither weather nor rivals could slow fifth-ranked Hovland, who won last week's BMW Championship and became the man to beat for the $18-million top prize.

Americans Collin Morikawa and Keegan Bradley shared third on 13-under with Masters champion Jon Rahm of Spain sharing fifth on 11-under with top-ranked Scottie Scheffler and his US countryman Wyndham Clark, the US Open champion.

Starting scores in the FedEx Cup playoff finale were staggered based on season points, with top-ranked Scheffler at 10-under, Hovland next at 8-under and rivals at lesser levels.

Hovland shot 68 and 64 to share the lead after the first and second rounds, aided by the unique format.