Emilio Gay and James Sales both set new landmarks as Northamptonshire continued to dominate on day two of their Vitality County Championship clash with Middlesex at Wantage Road.

First day centurion Gay forged on to post 261 – the highest ever individual Championship score for the county against Middlesex, while Sales brought back into the side for this game, made his maiden first-class hundred with his father David and mum Abigail in attendance to mark the moment. The pair set a new fifth wicket record against the Seaxes of 181 before the hosts declared on 552-6.

For Middlesex, who conceded 620 in the first innings against Glamorgan last week, it was another case of much leather chasing, Toby-Roland-Jones their only bowler to take more than one wicket (2-81).

There was still time in the evening session for two young debutants to make an impression, Raphael Weatherall capturing his maiden first-class wicket, while Middlesex teenager Nathan Fernandes (65 not out) reached an impressive half-century before stumps were drawn with the visitors 128-1, still 424 in arrears.

As they did on the opening day, Middlesex made an early breakthrough, Roland-Jones trapping Rob Keogh, the batter risking censure by taking his time to drag himself away from the crease, shaking his head as he went, a point noted by the two umpires.

However, as on day one, the wicket proved a false dawn for Middlesex as Gay and Sales embarked on their record stand.

Gay timed the ball exquisitely straight driving first Ethan Bamber, then Roland-Jones to the fence as he eclipsed Stephen Peters’ record score against Middlesex at Wantage Road, a 183 set in 2010.

It wasn’t long before he flicked a loose one from Tom Helm to the fine leg fence to reach his first double hundred and take Peters’ record of the highest ever score against Middlesex of 199 made in that same summer 14 years ago.

Josh De Caires would give him a reprieve almost immediately afterwards, failing to hold onto a tough caught and bowled opportunity. In De Caires’ defence he probably saved four not to mention himself being decapitated by the blow.

Sales meanwhile got underway with a four through midwicket and later took heavy toll of a De Caires over, clubbing one just beyond the grasp of mid-on before driving a better shot straight in the same over on his way to 50 from 109 balls.

The hundred stand was raised by lunch as Middlesex rattled through 22 overs in the second hour’s play to rectify a previously negative over-rate.

Gay was granted a second life soon after the resumption when Bamber failed to hold an even tougher caught and bowled close to the ground and celebrated the reprieve by hoisting De Caires back over his head for the day’s first six on route to 250.

The record fifth wicket stand against Middlesex of 131 between David Capel and Nigel Felton set at Lord’s in 1989 was soon eclipsed and it was a surprise when Gay’s innings was ended via a runout.

Saif Zaib sparkled briefly, striking one six out of the ground, before all eyes fell on Sales. Already having surpassed his career-best, the 21-year-old right-hander banished any thoughts of the nervous 90s with a huge six of his own before a scampered single took him to the century to a great reception from an albeit sparse crowd.

The declaration came soon afterwards and while Middlesex openers Mark Stoneman and Fernandes survived a testing 35 minutes before tea, Weatherall’s golden moment came soon afterwards.

The youngster, who played in the England U19 Test on this ground last September took just eight balls to find the edge of Stoneman’s bat, the tickle carrying comfortably through to McManus.

That one stuck for McManus but he was grass another when Fernandes was on 24, so denying Weatherall a second victim from his opening burst.

The left-hander made the most of the reprieve, to reach a 50 including seven fours, while Max Holden survived a drop at short leg on 35 to be 40 not out at the close.