Gunnar Krantz, on Swedish Match, reported gales, a ripped spinnaker and high speeds as he maintained a margin of more than 320 miles over the second-placed Knut Frostad in Innovation Kvaerner.
A relieved Krantz had felt like "a hunted animal" as the boats in fourth to ninth places made ground on his boat, which had been slowed by lighter winds near the Kerguelen Islands.
Swedish Match is now on the run again, averaging 19 knots in 40-knot winds, and Krantz expects to be in Fremantle next Monday.
Frostad, meanwhile, had experienced "one of my hairiest rides behind the wheel", his crew also having to clear lumps of seaweed from the keel.
A crewman on Paul Standbridge's third-placed Toshiba was injured when a turning block, controlling the topmast backstay, exploded. Australian David Blanchfield suffered bruising and is confined below.
Fourth-placed Paul Cayard was easing EF Language into a more comfortable lead over Lawrie Smith in Britain's Silk Cut, while his all-women counterparts on EF Education were just, but only just, holding off Grant Dalton in Merit Cup.
WHITBREAD ROUND THE WORLD RACE (second leg, 4,600 miles, Cape Town to Fremantle): Latest positions: 1 Swedish Match (Swe) G Krantz 1,718 miles to finish; 2 Innovation Kvaerner (Nor) K Frostad 328 miles behind; 3 Toshiba (US) P Standbridge 465; 4 EF Language (Swe) P Cayard 643; 5 Silk Cut (GB) L Smith 694; 6 Chessie Racing (US) M Fischer 706; 7 EF Education (Swe) C Guillou 808; 8 Merit Cup (Monaco) G Dalton 811; 9 Brunel Sunergy (Neth) H Bouscholte 851.Reuse content