Arsenal battled to overcome a resilient Ipswich Town 3-0 on Tuesday before reaching the League Cup final where Arsene Wenger's men will hope to end their six-year wait for a trophy.
Cesc Fabregas added the third after 77 minutes to see Arsenal through to next month's final at Wembley Stadium 3-1 on aggregate.
Arsenal, who have not won a trophy since lifting the FA Cup in 2005, will now meet either West Ham United or Birmingham City who play the second leg of their semi on Wednesday with the Hammers 2-1 ahead after the first leg at Upton Park.
Bendtner put Arsenal ahead after 61 minutes with a goal of the highest quality, controlling the ball superbly with the outside of his right foot before a flick and a cut inside took him past Carlos Edwards and allowed him to curl the ball past Ipswich keeper Marton Fulop.
Koscielny scored a second two minutes later when he powerfully headed home from a corner and Fabregas made it 3-0 after a breakaway.
Wenger chose a near full-strength side but they faced an immediate challenge before any of their players had touched the ball when Grant Leadbitter shot from the halfway line straight from the kickoff.
The ball only just went over the crossbar, although goalkeeper Wojciech Szczesny had it covered.
Arsenal, as was to be expected, then dominated much of the match with Ipswich penned in their own half for long periods while the Gunners squandered chance after chance.
They should have taken the lead when the unmarked Robin van Persie headed Bentdner's cross against the bar after 25 minutes, but Ipswich defended well even if they did not create another serious opportunity of their own.
Edwards, Damien Delaney and Darren O'Dea all kept Arsenal at bay until the opening goal, but once Arsenal made the breakthough the final outcome was inevitable.
