Man-of-the-match Riki Wessels clouted 64 from 38 balls as the Outlaws’ 174 for six proved too much for their hosts, despite a rapid 67 from skipper Kyle Coezter.
The Steelbacks’ slim hopes of getting out of the group, and keeping their defence alive, were therefore ended after a disappointing campaign.
For the Outlaws, they can now set their focus on securing a home quarter-final for the fifth successive season.
Victory at Yorkshire Vikings on Friday night will ensure the target of bringing knockout Twenty20 cricket back to Trent Bridge is achieved, even if the Outlaws have exited on that stage in the past three seasons.
The Outlaws, having won the toss on a fresh Wantage Road surface, made an expansive start.
Steven Mullaney took four boundaries off the second over bowled by David Willey and he was quickly joined by Alex Hales who launched his fourth ball into the members' pavilion.
The England man added a handful more boundaries before dragging an attempted pull on from Steven Crook and Mullaney, once the powerplay had concluded, lofted Muhammad Azhar Ullah to long-leg.
A period of consolidation followed as Wessels and Samit Patel prevented any more blood-letting while maintaining a respectable rate.
The hundred came up in the 13th over with the expected acceleration following, Wessels doing the majority of the damage.
His fifty, which occupied 30 balls, arrived a delivery after Willey, who had just concluded his three-over stint which went for 49, had put him down at long-on.
The pair’s century partnership, which took up 11 overs, came just before Patel lofted Crook to long-on.
At this stage, a total nearing 200 appeared on the cards but the loss of four wickets in the final three overs, Wessels among them and Crook finishing with the excellent figures of 3-19, meant the score posted was a gettable 174 for six.
Not that it would have looked that way three overs into the response with both Willey and Richard Levi, to successive Ajmal Shahzad deliveries, having an early shower.
Adam Rossington did not do too much as he hit James Franklin over the midwicket rope before chipping tamely to long-off, but Coetzer and Crook took the score to 64 for three at the midway point.
That left 111 runs needed from 60 balls, not particularly easy but definitely possible, and this had been reduced further before Crook dragged Patel to long-on.
Coetzer reached 50 for the first time this year and while he was at the crease there was a chance. That hope eroded when he fell for 67 at the end of an outstanding Harry Gurney over, the 18th, although the England man was forced off after it with an injury.
Speaking afterwards, Wessels said: “We were disappointed coming in having been 160 for two but it was a conscious effort to go hard with eight wickets in the bank.
“Our bowling has been our strength in the past few games and we haven’t put as many runs on the board as we would’ve liked.
“But Fletch (Luke Fletcher), Harry (Gurney) and Aj (Shahzad) have really pulled it back for us.”
In the home side’s camp, captain Coetzer said: “We needed to get off to a good start and I thought they bowled really well.
“They picked up a couple of early wickets and that put us on the back foot right from the start.
“They took us on early and maybe we didn’t hit the length we wanted to hard enough but we pulled it back really well.”