Smith struck 50 for the hosts
Ryder's 47 put Essex in contention
Patel took 4-20 to send Notts through
Notts reach Finals Day on 20 August
And that concludes are coverage of the first T20 Blast quarter-final.
Nottinghamshire, having posted 162-7, bowl Essex out for 123 to wrap up a thumping 39-run victory.
We'll be back for the second of four last-eight ties tomorrow, when Northants take on Middlesex. We'll see you then for a 18:30 BST start.
WICKET Foster (c Wessels b Gurney) 4
Nottinghamshire are heading to T20 Blast Finals Day!
James Foster is the last man out - a similar method, straight down the throat of Riki Wessels on the leg-side boundary rope - to put Essex out of their misery.
Well played, Notts.
Essex 122-9 (18.2 overs) v Notts 162-7
Oh my, does that just about sum this Essex batting display up?
Paul Walter is made to look a bit daft here, getting down on one knee in preparation to send Harry Gurney out of the park... But the slower ball deceives him, he checks the shot and just helps it straight into the hands of Chris Read. It just looked all a bit tame.
Image source, Getty ImagesIs that the over that confirms what we probably already knew?
New batsman Paul Walter does manage to clatter Steven Mullaney for six, but the medium-pacer ends with figures of 2-16 - plus the crucial run out of Jesse Ryder earlier - as part of what's been a crucial contribution.
Essex 113-8 (17.3 overs) v Notts 162-7
In a word, no.
Having been dropped first ball - a tricky chance off the bottom edge of the bat - Graham Napier attempts the big sweep, but can only spoon it up into the air for Imran Tahir to take a back-pedaling catch. This is getting messy.
Essex 113-7 (17.1 overs) v Notts 162-7
But Dan Lawrence, like so many before him, doesn't last too long either, caught smartly down the leg side by wicketkeeper Chris Read off the bowling of Steven Mullaney.
Now then, Graham Napier. Can you make this even a bit interesting?
Essex need 50 from 18 balls
Dan Lawrence is the next man in, but surely a crisis like this calls for the big-hitting of Graham Napier? If anyone can rescue a situation like this, I reckon he's your man.
Nonetheless, Lawrence, accompanied by a runner, reverse sweeps his first ball for four. And then takes a couple of singles to leave Essex needing 50 from 18 deliveries.
Essex 105-6 (16.2 overs) v Notts 162-7
If you hadn't quite caught on already, Nottinghamshire are heading for T20 Blast Finals Day!
Ravi Bopara is the latest to hole out to cow corner, where Riki Wessels takes the catch off the bowling of Imran Tahir.
Well bowled, Samit Patel. He has T20 best figures of 4-20. Essex need 59 runs from 24 balls.
Essex 103-5 (15.5 overs) v Notts 162-7
Image source, Getty ImagesThat looks plum jam from Samit Patel, who traps Ryan ten Doeschate in front to take four wickets in a T20 match for the first time in his career. A real favourite with the crowd, that'll be a popular four wickets too.
And it's top stuff again from Imran Tahir, who concedes just six runs and continues to have Essex behind the eight ball.
The required run rate is now up to 12, the WASPS is now down below 10%. One of these two need to get the hurry up, but Samit Patel's coming back to bowl his fourth and final over.
Essex need 69 from 36 balls
Steven Mullaney hasn't taken a wicket, but he's been superb with the ball here - just eight from the 18 balls he's bowled.
It's all been about pace off the ball - Samit Patel has taken three of the four wickets to fall, and now Imran Tahir is back into the attack.
Ravi Bopara and Ryan ten Doeschate have seen this all before though, right? Two experienced campaigners, well used to the big stage.
The run rate, however, is now over 10. A tall order getting taller.
... But the hat-trick ball is survived.
The crowd is absolutely bouncing inside Trent Bridge now, as the WASPS declines further to 22%. Someone, somewhere, somehow is going to have to produce something a bit special with the bat if Essex are to reach Finals Day.
Essex 87-4 (12.1 overs) v Notts 162-7
Clean bowled! Nottinghamshire are rampant!
And Ryan ten Doeschate now has the good pleasure of walking in to face a hat-trick ball from Samit Patel...
Ravi Bopara is the next man in and it's a steady start from the former England all-rounder, as he and Tom Westley trade singles. They're still stuttering here though, are Essex.
Essex 82-3 (11 overs) v Notts 162-7
A huge, huge six... And out!
Same delivery, same attempted shot, but a very, very different result for Ashar Zaidi, who only picks out Riki Wessels at long on. Who's your money on now?
Essex 82-2 (10.5 overs) v Notts 162-7
Ashar Zaidi's first ball... Six! A huge, huge six!
Essex 76-2 (10.4 overs) v Notts 162-7
Image source, Rex FeaturesAnother one goes!
Nick Browne's resistance is ended, holing out to cow corner off Samit Patel, where Jake Ball stutters, steadies himself and pouches the attempted heave-ho.
The WASP is plummeting - down to 61% now! We've got a game on, folks!
Just two more from that latest Steven Mullaney over, and we're without a boundary since Jesse Ryder's departure.
It's all to play for at the midway stage.