Glamorgan batter Sam Northeast hit 410 not out against Leicestershire – the third highest score in County Championship history.
Northeast reached his quadruple century before lunch on day four at Grace Road.
His score is the highest in the Championship since Brian Lara’s 501 not out for Warwickshire in 1994 and the best of the 21st century.
Glamorgan declared at lunch on 795-5, denying Northeast, 32, the chance to pass the West Indies legend’s total.
Only Lara and Archie MacLaren, who hit 424 for Lancashire against Somerset in 1895, have made higher County Championship scores than Northeast.
Graeme Hick is the only other player who has made a quadruple century in the Championship, when he made an unbeaten 405 for Worcestershire against Somerset in 1988.
Northeast’s innings also took him beyond Steve James’ previous best for Glamorgan, which was 309 not out.
Northeast’s stand of 461 with Chris Cooke, who finished unbeaten on 191 – was also the biggest for Glamorgan.
A record-breaking session in Leicester
Glamorgan were 21 runs behind overnight, but plundered 232 on the fourth morning, with both batters scoring hundreds in the session.
After resuming on 308, Northeast needed just two runs overnight to beat James’ mark after a marathon eight-hour effort.
He took a single, then set the Glamorgan record with a four off Chris Wright, but the Foxes missed a run-out chance immediately afterwards.
Leicestershire finished with nine fielders around the boundary in a bid to limit the damage, but Northeast reached 400 with the second of his three sixes to go with 45 fours, rarely playing a false shot as he pierced the field regularly.
Cooke struck 19 fours and three sixes at the other end in an innings which would have taken the headlines on any other day.
Their partnership was the biggest for the sixth wicket in the competition – and overtook the 425 set by Sir Viv Richards and Adrian Dale as Glamorgan’s best stand.
James’ score was posted against Sussex at Colwyn Bay in 2000, the first treble century for the Welsh county – a match which had also seen the highest team score of 718-3.
Former Kent and Hampshire captain Northeast also passed 1,000 runs for the Championship season in his first summer with Glamorgan.
His tally of 258 on the third day of the match at Leicester represented the most scored by a Glamorgan player in a day, 20 more than the previous best by current coach Matthew Maynard.
