He drove Eric's Legend and Aylesham to win at Forbury Park last night, taking his tally for the season to 66 wins.
He has seven drives at the Marlborough meeting at Waterlea today.
He is then on a flight to Auckland to drive Mach Banner and Flaunt It tonight.
Mach Banner is a leading prospect for the feature race for 2yr-olds.
Dunn will have come through a daunting travel schedule to drive at the three venues.
He travelled by road from West Melton to Dunedin yesterday and returned home after the last race.
He was able to share the driving on the round trip of nine hours with his brother, Dexter, Robert Butt and Tim Williams.
They expected to be home about 3 am.
John and Dexter are due to leave for Blenheim about 6.30am, another four-hour road trip.
John is on a flight from Blenheim to Auckland at 4.40pm.
Eric's Legend was within 0.6sec of the track record when he ran 2.41.7 for 2200m (mobile) after leading.
He came away to win by six lengths after sprinting the last 800m in 56.9.
The New Zealand record for a 3yr-old is 2.40.2, held by Justa Tiger (2007).
Aylesham, at odds of 30 to one, is trained by Forbury Park club committee member Ray Hanson who races the 4yr-old with Ken Campbell and Barry Dent.
Armbro Winger is another success story for owners Graeme Anderson (the Westwood Beach trainer) and Trevor Nicholson, of Arrowtown, with a horse bought from trainers Tim Butt and Phil Anderson.
Armbro Winger transferred to Anderson after his previous start a fortnight ago.
"We bought him with the money we have earned from Ants," Anderson said.
The trotter Ants has won five races and $27,000 since being bought out of the Butt-Anderson stable in March last year as a two-win horse.
Dexter Dunn set a leisurely pace with Armbro Winger, who sprinted his last 800m in 57.2 to win by a long neck.
