Toby Roland-Jones finished with a career-high 12 wickets in the match as Middlesex beat Northamptonshire by an innings and 84 runs to go top of Division One.
Northants were bowled out for 176 in their second innings at Wantage Road, Roland-Jones adding figures of 6-50 to go with his 6-55 in the first innings.
Starting the final day on 88-4, Northants needed another 172 just to make Middlesex bat again.
The home side quickly slipped to 103-7 before Ben Duckett (56) and Ian Butler (14) resisted for almost two hours either side of lunch.
The eighth-wicket pair put on 62 in 38.2 overs but seamer Roland-Jones removed both in quick succession as Middlesex sealed the win in mid-afternoon.
Middlesex's fourth County Championship victory of the season gives them a 19-point lead over Yorkshire at the head of Division One.
At Taunton, Somerset closed day three on 112-0 in pursuit of a target of 248 against defending champions Durham.
Openers Marcus Trescothick (58no) and Johann Myburgh (48no) took an aggressive approach in the evening session, hitting 18 fours between them. Somerset will resume on the final day needing a further 136 runs for victory.
Durham had earlier collapsed from 180-1 to 326 all out in their second innings.
Mark Stoneman and Michael Richardson extended their second-wicket stand to 161 in the first hour of the day before Somerset's bowlers hit back.
Stoneman was denied a century when he edged behind off Craig Overton for 97, the first of a maiden five-wicket haul for the young seamer.
Richardson did manage to complete his second hundred of the season - and the fourth of his first-class career - before being bowled by Craig Overton (5-63) for 116.