The result denied second-placed Worcestershire the chance to take over at the top of the table from Lancashire, now two points ahead of Worcestershire and visitors to New Road for the last match of the season on 19 September.
After his side had slipped to 136 for 4 chasing 207 to win, Knight found a reliable partner in Michael Powell, whose undefeated 45 included five fours off 42 deliveries.
Earlier, Worcestershire's total of 206 for 6 was boosted by a fine 89 from the acting captain, Graeme Hick. He put on 142 in 39 overs with Elliott Wilson, whose 62 was his best score for Worcestershire.
Kent kept their title hopes alive with an 82-run win over relegation- threatened Hampshire at Canterbury, leaving them two points behind Worcestershire, who have a game in hand. Trevor Ward was top scorer with 36 for Kent, who were left to defend a modest 188. But they bowled Hampshire out for 106 as the visitors failed to recover from their early troubles at 20 for 3.
Nottinghamshire completed a double over neighbours Derbyshire with a 138-run win at Derby. Jason Gallian hit 130 to steer Nottinghamshire to a daunting 286 for 6 and a much more convincing victory than Sunday's eight-run scramble at Trent Bridge. Derbyshire's last six wickets fell for 26 runs and a total of 148, leaving them disputing the wooden spoon with Durham and Middlesex.
Northamptonshire virtually sealed promotion to the top flight with a 27-run win over Durham at Wantage Road. Graeme Swann celebrated his England call-up for the winter tour of South Africa, hitting 19 runs off as many balls in the home side's 227 for 7.
The 20-year-old all-rounder, who received his Northamptionshire cap from the acting skipper David Ripley, then claimed 4 for 44 with his off-spin as well as catching Jimmy Daley and running out Martin Speight. Durham rarely threatened to reach their target, despite Paul Collingwood's gallant 86 from 109 deliveries, and they were dismissed for 198.Reuse content