Bowler TJ Watson cleaned up the tail to take 4-25 in his seventh over.
In reply, Central needed to get to 200 before 40 overs to pick up the crucial bonus point and finish tied for runner-up on the table, which they did with nine balls to spare, reaching 200-3 in the 39th over.
The chase was led by a superb 116 not out from 104 balls by opener BL Wiggins.
It was a big turnaround from the day before when Central were bowled out by Wellington for 77, with the No11 O'Connor being the last to fall for four runs in the 27th over.
Raj said the team had not come back well from having to sit around while the weather cleared from Monday.
"The rain crippled us, and we struggled the day after. We had three days and no cricket.
"Then you had eleven guys playing as individuals."
Wellington reached their target in the 15th over, with O'Connor finishing with 0-25 from his four overs.