Northamptonshire succumbed to their third straight innings LV= Insurance County Championship defeat on the third day against Hampshire.
Dawson claimed six for 61 for his sixth first-class five-for and his best figures at the Ageas Bowl to reignite Hampshire’s title hopes after two winless matches with the innings and 135 run victory coming inside three days.
Northamptonshire, who have one win and a solitary batting bonus point so far this season, only claimed three points from the match as they bottom of Division One.
Whiteman and Keogh resumed the day with the task of batting long ahead of them. The duo batted out 39 of the first 42 balls of the day as dots and took little risks, while starting to nibble away at the deficit.
Whiteman would face 93 balls and Keogh 113, but after an hour of occupation under stunning blue skies, it was the introduction of spin that proved the difference.
Dawson’s second over of the day was long enough to see Australian Whiteman attempt a drive out of the rough, only to get bowled through the gate.
Ricardo Vasconcelos also took the attacking route out but missed his sweep as the ball turned sharply out of the rough to leave his stumps exposed.
Keogh had been dropped earlier in the morning by Dawson before the left-arm spinner had him leg before with an arm ball. Northamptonshire now 150 for five having been 89 for two little more than 10 overs earlier.
Mohammad Abbas had James Sales lbw with the first ball after lunch to begin a post-interval collapse of 33 for five.
Dawson was fortunate to have Tom Taylor adjudged LBW for a pair, before Jordan Buckingham went back to another one which went on with the arm.
Saif Zaib – who had been the only Northamptonshire batter to reach double figures in the first innings – again impressed with a 78-ball fifty. He showed application, mixed with some attractive shot-making to end up unbeaten on 57.
But Dawson kissed the top of Jack White’s off stump with a ragging delivery and Mason Crane – on his first appearance of the season – got Alex Russell to edge to first slip to end Northamptonshire’s disappointing trip to the south coast at 2:40pm.