Patel scored an undefeated 129 as his side reached their victory target of 239 with five balls remaining. The 28-year old had arrived at the crease in the sixth over, after Notts had lost both Alex Hales and Michael Lumb inside the first six overs, and hit 12 boundaries and four towering sixes in his 123-ball knock.
Notts lead Group A from Northamptonshire, who enjoyed a 63-run victory over Sussex at Arundel where Stephen Crook took three wickets in 11 balls. After the Steelbacks had made 191 for six from their 39 overs, Crook laid waste to Sussex's top order by removing Chris Nash for one and Luke Wells and Ed Joyce for ducks while David Willey picked up Luke Wright as the Sharks were reduced to seven for four in the sixth over.
Mike Yardy (52) and Ben Brown (40) gave Sussex some respectability but they were bowled out for 128 in the 35th over and a third defeat has left them struggling to make the semi-finals for the third year in a row.
Holland clinched their first Yorkshire Bank 40 victory of the season as they beat Worcestershire by six wickets in a match reduced to 18 overs a side at New Road. Worcestershire were restricted to just 90 for six before Tom Cooper (29no) and Daan van Bunge (25) carried the Dutch to victory.
Durham bowled Scotland out for 91 before wrapping up a seven-wicket triumph at Chester-le-Street as the visitors' miserable form in the competition continued.
Essex fell to second in the group as they lost at home to Lancashire by 64 runs, with Simon Katich and Glen Chapple once again putting them to the sword. Katich made 60 as Lancashire reached 230 for eight and Chapple took three for 33 as Essex were bowled out for 166.
Somerset remain top of Group C after Craig Meschede helped them to a five-wicket victory over Leicestershire at Taunton. The 21-year-old confirmed his position as the leading wicket-taker in the competition by claiming four for five, moving him to 20, as the visitors were restricted to 124 all out in a match reduced to 25 overs per side by rain. Craig Kieswetter made 50 and Marcus Trescothick 28 in the reply.
However, neighbours Gloucestershire are keeping the pressure on after producing an impressive all-round performance to beat Yorkshire by 36 runs in a match reduced to 27 overs a side. Chris Dent top-scored with 56 and there were useful contributions from Michael Klinger and Ian Cockbain as the home side posted an imposing 229 for six.
Dan Hodgson made 76 in the reply for Yorkshire but they were always behind the run rate before being bowled out for 193 with three balls remaining, David Payne taking four for 44.