Sampath Bandarupalli is a statistician at ESPNcricinfo
1 Tom Haines (243) and Cheteshwar Pujara (201*) became the first pair to score double-centuries in the same first-class innings while following-on. They are also the first pair with double-hundreds in the same first-class innings for Sussex since Ted Bowley (228) and Maurice Tate (203) in 1921 against Northamptonshire.
2 Pujara became only the second Indian to score a double-century in the County Championship. Mohammad Azharuddin was the first, having scored 212 against Leicestershire in 1991 and 205 against Durham in 1994, both for Derbyshire. Iftikhar Ali Khan Pataudi also had four double-hundreds in County Cricket, but were scored while he was a Test cricketer for England.
52 First-class innings without a hundred for Pujara before the unbeaten double-ton for Sussex. His last first-class century was scored in January 2020 when he made 248 against Karnataka. Between his recent two hundreds, Pujara scored 1518 runs in the format at an average of 30.36 with 14 fifties.
14 Number of first-class double-centuries for Pujara, the most by an Asian player. He has now surpassed Kumar Sangakkara's tally of 13 double-tons. Only eight batters had more first-class double-hundreds than Pujara. No active player other than Pujara has even scored ten double-tons.
1 Pujara's 14 double-centuries in first-class cricket are also the most by any player in the format since the start of the 21st century. Sangakkara held the record previously as all his 13 double-tons came between 2002 and 2017.
201* Pujara also recorded the highest individual score on the first-class debut for Sussex. The previous highest score on debut for Sussex was 152 by Joe Gatting against Cambridge UCCE in 2009.
239 Shan Masood's score during the Derbyshire's first innings. It is the highest individual score by a Pakistan player in the County Championship. The previous highest was 230* by Zaheer Abbas for Gloucestershire against Kent in 1976.
3 Number of players to score a double-century in the game between Derbyshire and Sussex - Masood, Haines and Pujara. It is only the third County Championship match to feature three double-centurions. The County Ground in Northampton stood host for the previous such instances when the home team Northamptonshire faced Essex in 1952 and Glamorgan in 1998.