The Denton-trained Och Aye The Noo is a trotter in the form of her life, and bounced away off her 40m mark to win the c1-c6 2700m trot by 6 lengths in a time of 3.27.5.
Her corrected time was 0.4sec inside the track records for both genders - breaking Here Comes Pat's 2012 mares' record of 3.28.8 and also David Moss' 1993 time of 3.27.9.
Cox's father, John, was the trainer of David Moss at the time of his 1993 track record and Cox junior was able to describe the giant trotter's 10-length win in detail 22 years on.
However, it is Och Aye The Noo making the headlines now, and Cox said the mare was a pleasure to drive.
''She's come a long way since this time last year,'' he said.
''It's just time and racing with a lot of trotters - the more miles they do, the better they become and she's a prime example of it.''
Nathan Williamson extended his season record to 41 wins at Forbury Park last night when he steered home Kiwi Focus to her second consecutive win.
Williamson set a Southland trainers' record two seasons ago with 35 wins and followed that up with 31 wins last season, but credits his ever-increasing mark this term to two smart sophomore pacers.
''I had some really nice 3yr-olds - with Statham and Tas Man Bromac, there's 10 wins and that's the difference,'' he said.
Onedin Mach, Poppymalda, Sue Me, Grey Power and Booster were other multiple race winners for Williamson, along with a cast-off from his father, Phil Williamson, called Dwindle Mist.
''She had arrived from Dad's and she was finished, and I ended up getting her and she went pretty good.''
Westwood Beach trainer Graeme Anderson was laid up at home last night with a sore back, so missed being on course for what he believes is his first training trifecta.
Starsky's Dream sizzled home in 3.20.9 for the 2700m on a cool night, and was chased home by stablemates Match Point and Onedin Mach to complete the impressive training feat for Anderson.
''I don't train enough horses to have that chance too often,'' Anderson said by phone.
Starsky's Dream was driven by Dexter Dunn, who also won with Diamond King, Suzie's Gem and Highview Anwell to bring his season winning tally to 193.
The Edge Of Reason broke maidens at his 28th start, having looked close enough to gaining a win over his career without ever quite getting there.
Driver Craig Ferguson opted to take the son of Lis Mara to the lead shortly after the start of the 2200m pace, and he rolled along to win by a head from Lauras Legacy.
Ferguson's win with The Edge Of Reason was his 35th for the season, after scoring in the previous race with Lamborne Road.
He takes a two-win lead over Stevie Golding in the junior drivers' premiership, although Golding has four drives at Waterlea today.