Northamptonshire’s bowlers were made to work hard for wickets on an Ageas Bowl surface offering little on the first day against Hampshire.
Alex Russell made his first-class debut with James Sales the pick of the bowlers with two for 32, while Jack White claimed two for 65.
Hampshire won the toss and elected to bat in conditions that pointed towards runscoring being the easier discipline.
Hampshire pushed hard with a mixture of skill and fortune in the first half an hour as Middleton and Joe Weatherley raced out of the blocks.
The pair scored 12 in the first over and were up to 22 after the second as the first 31 minutes saw the half-century stand arrive in only 46 balls. But Jordan Buckingham brilliantly angled in and seamed away to bowl Weatherley to halt and swing the momentum.
Northamptonshire had by no means disgraced themselves in that avalanche of runs with a number skewing off the edge through third man, but slightly tighter lines and a slightly softer ball stemmed the runs and built pressure.
The remaining 90 minutes of the session saw just 45 more runs with a full Sales delivery proving too quick for Middleton and rattling his stumps and the bogged-down Nick Gubbins leg before to Jack White.
Vince had arrived and was joined by Brown; the two experienced pros refused to allow a collapse similar to that which turned their last home fixture with Warwickshire into a catastrophe.
Vince was patient, especially against the nagging accuracy of Sales and Tom Taylor – his 50 coming up in 100 balls.
Brown was equally sedate in the 106-run stand, although earned a life when he was dropped at second slip before he was eventually bowled chopping on Sales.
Vince quickly moved on to partnering up with Dawson and another fruitful stand; this time worth 75.
But hopes of a 29th first-class century were thwarted in the over before the second new ball as an innocuous forward prod to Rob Keogh was tickled behind. Ian Holland followed when he was lbw to White with the new cherry.
Dawson continued from his 84 against Kent last week to end the day’s landmark curse with his fifty coming in 79 balls, during an unbeaten 50 stand with Keith Barker.
On first-class debut, leg-spinner Alex Russell, 21, showed high promise with a number of challenging deliveries despite going wicketless.