Goodwin copied Jimmy Hildreth as this year's second Taunton triple centurion
Murray Goodwin hit a career-best 344 not out to break his own county record as he helped Sussex rewrite the history books against Somerset at Taunton.
The Zimbabwean batsman hit the second triple century of his career as Sussex broke a 107-year-old record by running up their highest-ever score, 742-5 dec.
Goodwin shared a 363-run county fourth-wicket record partnership with Carl Hopkinson, who hit a career-best 139.
Somerset replied on their batsmen's paradise of a pitch on 126-0.
Marcus Trescothick hit 55 and Arul Suppiah 61 as they prepared the ground for a potential long stay of their own at the crease on Friday.
Sussex's record-breaking efforts, spectacular though they were, still stopped short of a complete rewrite of the Taunton records.
BIG TOTALS AT TAUNTON
850-7 dec Somerset v Middlesex, April 2007
801-8 dec Derbyshire v Somerset, May 2007
801 Lancashire v Somerset, 1895
742-5 dec Sussex v Somerset, August 2009
Goodwin's knock was still only the third highest at the County Ground, well short of Archie MacLaren's 424 for Lancashire in 1895 - and the more recent and better celebrated 405 not out compiled by a young Graeme Hick for Worcestershire in 1988.
There have also been three higher team totals. But the day still belonged to 36-year-old Goodwin, who beat his own previous county best of 335 not out, set against Leicestershire at Hove in 2003.
Building on Chris Nash's career-best 157 on Wednesday, Goodwin also helped set a new Sussex record score, beating the previous best of 705-8 dec against Surrey at Hastings in 1902.
Goodwin's score, the sixth-highest in the history of county cricket, lasted 351 balls, containing 43 fours and six sixes.
Having started the day on 96, he reached the 60th first-class century of his career off the first ball of the morning, dispatching leg spinner Max Waller to the mid-wicket boundary.
It was Goodwin's first three-figure score of the season but a lot more was to come.
Together with Hopkinson, the Sussex pair plundered runs almost at will until, with the total on 676 (and the 326 shared by James Langridge and George Cox against Yorkshire at Headingley in July 1949 now surpassed), their new county record fourth-wicket partnership was finally broken.
Suppiah bowled Hopkinson then, just three balls later, did the same to Dwayne Smith.
But Goodwin brought up the 700 with successive sixes over mid-wicket off Suppiah and remained until tea, at which point Sussex declared.
Facing a testing final session, the country's top run scorer Trescothick and Suppiah then made it look similarly easy.
Record-breaking batsman Murray Goodwin told BBC Radio Sussex:
"It's nice to get a few runs and nice to get records but you've got take into account that the wicket's pretty flat, as flat a wicket as I've ever played on.
"And, as a batsman, when that happens, you've just got to fill your boots.
"The way I was playing in practice, I always thought I'd get a big score sooner or later.
"But, as it stands, this game looks like a draw. The wicket's not breaking up at all and it doesn't look like there'll be a result. But you never know."
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