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
That WASP has gone down from 89% to 74%, which suggests Essex are still firm favourites but the hosts are back in this T20 Blast quarter-final.
Nick Browne is still unbeaten on 20 from 21 balls, while the new man Tom Westley has three from four.
Samit Patel's first over goes for just four - and every dot ball is being cheered and applauded by the Trent Bridge crowd now.
A turning point? You never know. After that wicket, just three more runs come from that Steven Mullaney over and the Essex progress has been well and truly checked, at least for now.
Tom Westley is the new man in, Samit Patel is into the attack.
Essex 65-1 (7.1 overs) v Notts 162-7
How about this for a spot of luck for Nottinghamshire?
Steven Mullaney is into the attack and has a wicket from his first ball - but perhaps not in the way he'd have expected.
Nick Browne straight drives the medium-pacer back down the ground, but Mullaney gets a touch attempting to field the ball, diverts it onto the stumps and Jesse Ryder is stranded backing up.
That's much more like it from South Africa leggy Imran Tahir, whose latest set of six goes for just three runs.
The end of the powerplay
That's been a very decent first 36 balls for the visitors.
Harry Gurney's second over goes for 12, another two via the rope from the bat of Jesse Ryder - the second of which was half-stopped by the fielder on the edge of the ring, but was still hit so powerfully that it rolled to the boundary.
Essex need another 101 to win.
The 50 partnership for Browne and Ryder
Jesse Ryder has his eye well and truly in here, spanking Imran Tahir's second ball for a thumping four into the offside. The pattern is clear, too - the Kiwi is all about power for the first four deliveries of each over and then meanders up the other end to let Nick Browne deal with the final ball.
The 50 partnership is up and Essex are in command.
Image source, Rex FeaturesThese two love a four. Eight from the first four overs, 44-0.
Jesse Ryder is the man doing the majority of the damage, 28 from 17 balls, while Nick Browne is just ticking along with 10 from seven.
Imran Tahir is into the attack - a change of pace and a change of luck for Nottinghamshire?
Another productive over for the visitors, as Jesse Ryder clatters a couple of fours - one beautifully through the covers - before Nick Browne does likewise to move Essex to 34-0 after 18 balls.
WASP rates their chances at 89%, which speaks volumes for the start they've made.
Image source, Rex FeaturesFireworks? Not quite, but these two batsmen, by hook or by crook, keep Essex ticking along quite nicely.
Another four to Jesse Ryder, who races to 14 from nine deliveries, opens the second over up - before a no ball prompts a free hit, which in the end amounts to nothing much.
There is a little bit of a panic from the final delivery as both batsmen almost end up at one end, but Samit Patel misses when a direct hit would've brought about the first wicket with room to spare.
A first set of six, delivered by Luke Wood, of few real dramas.
A couple of fours from the timber of Jesse Ryder, a single to Nick Browne and Essex are off to a solid start.
Thanks Gary. Finely-groomed, indeed.
Right then, the players are back out on the field of play and we're all set to crack on.
Jesse Ryder and Nick Browne are at the crease, Essex need 163 runs to win.
Notts 162-7 v Essex (20 overs)
So, how will Essex fare? My finely-groomed colleague Brendon Mitchell will be back in about 10 minutes with the chase.
Notts 162-7 v Essex (20 overs)
Chris Read adds a little bit of panache to finish Nottinghamshire's innings, scooping Graham Napier for four and finishing it off with a quickly run two.
But you have to feel it's a below-par score on a flat deck and lightning outfield.
Graham Napier (2-20) and Ryan ten Doeschate (3-19) - both outstanding.
Notts 156-7 v Essex (19.3 overs)
If you thought Ryan ten Doeschate's evening couldn't get any better, it just has. Luke Wood pulls Graham Napier into the leg side and ten Doeschate dives forward to take a fine catch inches off the turf.
The good news for Notts fans is that Chris Read is on strike.
Chris Read smashes his first ball for four but it doesn't do much to dent Ryan ten Doeschate's bowling figures.
Four overs, 3-19. One to go, Notts need a biggie.
Notts 150-6 v Essex (18.4 overs)
I'm not a betting man, but if I was my money would be going on Ryan ten Doeschate for man of the match.
The Essex seamer picks up his third wicket for not very many as Samit Patel skews him to the point boundary and into the safe hands of Nick Browne.
Notts 146-5 v Essex (18 overs)
Nottinghamshire's innings is stumbling and stuttering over the finish line.
Graham Napier finishes the 18th over with a yorker which beats Steven Mullaney's defences and clatters into the stumps.
Two overs to go - what can the Outlaws muster?
Ryan ten Doeschate has been the stand out performer for Essex.
Three overs, 10 runs conceded, two wickets. Excellent.
Notts 136-4 v Essex (16.2 overs)
Oh dear, this has been the story of Nottinghamshire's innings so far.
Just as Dan Christian was beginning to time the ball sweetly, the Australian biffs Ryan ten Doeschate high into the blue evening sky and Graham Napier takes a decent catch.
Next ball Samit Patel edges the Dutchman behind but James Foster can't cling on. Notts are wobbling.
Is there a better touch player than Samit Patel when he's in form? The Nottinghamshire all-rounder carves Ravi Bopara through point and then flicks him through the same area next ball. Pure timing.
Can Notts get up to 180 from here?