Arnaut Danjuma scored a clinical counter-attacking goal to give Bournemouth a slender 1-0 advantage over Brentford in their Sky Bet Championship play-off semi-final.
Dutch winger Danjuma settled a tight first leg in the Cherries' favour by starting and finished a flowing breakaway move 10 minutes into the second half.
Bees substitute Bryan Mbeumo wasted a golden chance to restore parity ahead of Saturday's return match in West London when he somehow diverted wide of an open goal 12 minutes from time.
Backed by fans for the first time since December, Bournemouth also had opportunities to strengthen their hopes of a Wembley final against either Swansea or Barnsley.
Dominic Solanke saw a first-half header strike a post, while Philip Billing squandered a fine early opening.
Brentford finished 10 points above their hosts in the table but struggled to involve 31-goal striker Ivan Toney in the game, leaving them with work to do.
Thomas Frank's Bees arrived on a stormy south coast 12 games unbeaten, as well as having won each of the two league matches between the clubs.
Both managers opted for the continuity of unchanged starting line-ups.
Home fans – around 2,000 in total – were on all four sides of the ground and there were light-hearted boos as the visitors entered the field, followed by rapturous applause for the hosts.
In-form Brentford began in a slight ascendancy, yet it was the home side who had the major opportunities of a cagey opening period.
After Jefferson Lerma's powerful volley flew narrowly off target, the unmarked Billing, who was prolific from an attacking midfield role in the second half of the season, skewed horribly wide from around the penalty spot in the 12th minute after being picked out by rampaging right-back Adam Smith.
It was only the third occasion this season – after December wins over Huddersfield and Wycombe – that Cherries fans had been permitted inside the ground and the first time since Jonathan Woodgate replaced Jason Tindall as manager in early February.
The terraces were increasingly vocal as their team continued to get joy from out wide.
One-time England striker Solanke went closest to a first-half opening, nodding against the outside of the left post from a Lloyd Kelly cross.
Bees goalkeeper David Raya later denied a Steve Cook header following a corner just before the interval, with Toney on hand to block David Brooks' follow-up effort.
Captain Cook was then forced off – replaced by former Brentford man Chris Mepham – after suffering an apparent knee injury.
Brentford, beaten finalists last year, hold a dismal play-off record, having failed to gain promotion on each of the previous nine occasions they qualified.
They were struggling to threaten and paid a heavy price for committing men forward early in the second period as the deadlock was broken in style.
Danjuma helped dispossess Bees defender Pontus Jansson deep in Cherries territory and, after the ball was worked on by Solanke, raced more than 80 yards to slot Brooks' perfectly-weighted pass beyond Raya and into the bottom right corner to claim his 16th goal of the season.
With a trip to Wembley at stake, there were understandably nervy moments for Woodgate's men to negotiate.
Cherries keeper Asmir Begovic was alert to smother from substitute Emiliano Marcondes before being left relieved by Mbeumo's profligacy in the 78th minute.
The net looked certain to bulge when Christian Norgaard centred from the left but, with the goal gaping, unmarked substitute Mbeumo – who claimed the winner on this ground last month – slid in to somehow divert wide.
Danjuma had a thunderous free-kick pushed away by Raya in the closing stages, but most of the action was at other end as Bournemouth resolutely dug in to claim an important win and move on from a mini wobble of three successive defeats.
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