Lancashire claimed the bragging rights in the Roses clash against Yorkshire with a nine-run victory in front of a sold-out crowd at Headingley.
Young seamer Saqib Mahmood (three for 33) turned the match the visitors' way late on when he took the wickets of the dangerous Nicholas Pooran (43) and Dom Bess in the space of three balls.
Earlier, Lancashire captain Dane Vilas struck 43 from 24 balls while Yorkshire off-spinner Jack Shutt took two for 31 on his debut as the Lightning posted 170 for six.
2️⃣ completed games2️⃣ wins What a start to this year's @VitalityBlast 👌 — Lancashire Cricket (@lancscricket) July 25, 2019
England seamer Tom Curran claimed a hat-trick as Surrey dismissed Glamorgan for 44 – the lowest total in English domestic Twenty20 history – en route to a 97-run win.
David Lloyd, captain Colin Ingram and Billy Root were Curran's victims from successive deliveries in the second over as Glamorgan suffered a nightmare start to their pursuit of 141 at the Kia Oval.
🔥 @TC59 🔥 A hat-trick for our @englandcricket man! #Blast19 pic.twitter.com/IP3CX7nJWT — Surrey Cricket (@surreycricket) July 25, 2019
Curran finished with figures of three for three while spinners Imran Tahir (three for eight) and Gareth Batty (three for seven) also enjoyed impressive evenings.
Will Jacks' had led Surrey to their total of 141 all out as he top-scored with 40 off 26 balls, hitting two sixes and four fours in the process, while Marchant De Lange and Andrew Salter both picked up four wickets apiece for Glamorgan.
At Cheltenham, Gloucestershire won by two wickets to inflict a first defeat on Middlesex as local boy Miles Hammond delighted his home crowd with a brilliant array of shots.
Bloke is a freak🔥 glosters in fire in Cheltenham! Long may it continue🙏🏻 https://t.co/ilaEkuwyIB — James Bracey (@bobbybracey25) July 25, 2019
The 23-year-old opener smashed 63, including nine fours and three sixes, against a Middlesex side that were without star recruit AB De Villiers due to a hand injury.
Without him the visitors posted 148 for nine, with Stevie Eskinazi making 40 and John Simpson 42 not out.
