|Specsavers County Championship Division One, Trent Bridge, day one|
|Nottinghamshire 241: Patel 100; Finn 4-54, Rayner 3-46|
|Middlesex 9-3: Ball 3-2|
|Notts (2 pts) lead Middlesex (3 pts) by 232 runs|
Jake Ball took a hat-trick as Division One leaders Middlesex collapsed to 0-3 in the first over of their reply to Notts' 241 all out at Trent Bridge.
Ball, who made his England Test debut against Pakistan in July, removed Sam Robson and nightwatchman Ollie Rayner before trapping Nick Compton lbw.
The title-chasing visitors were 9-3 at the close on day one, trailing by 232.
Earlier, Samit Patel scored exactly 100 for bottom side Notts, while Steven Finn took 4-54 for the visitors.
Middlesex, who began the game four points clear of second-placed Yorkshire, appeared in control of the match despite all-rounder Patel's defiant century for the struggling hosts.
But any hopes of securing a sizeable first-innings advantage were severely dented by Ball's hat-trick, the second in this season's County Championship.
The 25-year-old's efforts earned a bowling bonus point for Notts, who must win to retain any realistic hope of staying in Division One, within five balls of Middlesex's reply.
The astonishing end to the first day's play came after a promising bowling display from Finn, who was back in the Middlesex side after featuring in England's recent Test series with Pakistan.
He struck with his third ball to bowl Tom Moores with a full inswinging delivery and also forced Steven Mullaney to edge to second slip before lunch.
Finn returned after some resistance by Notts' lower order to dismiss Brett Hutton and end Patel's stay at the crease, but not before the all-rounder had struck 16 fours and a six to register his second Championship century of the season.
Reaction to Ball's hat-trick
BBC Sport's live text commentator Phil Shepka described events at Trent Bridge as "absolutely nuts" as Ball left Middlesex 0-3 after five balls of their first innings...
While Nottinghamshire team-mates past and present offered their congratulations on Twitter...