Kettering Town and Corby Town will collide in the final of the NFA Hillier Senior Cup at Sixfields next month.
With the Steelmen having already booked their place in the county showpiece, the Poppies joined them after claiming a 1-0 victory over a strong Brackley Town side at Latimer Park.
Kettering turned in a decent defensive display with youngster Jack O’Connor impressing in another start in midfield.
There were few chances at either end but the Poppies grabbed the only goal of the game in the second half when, after good work from Nathan Hicks, James Hall beat former Kettering goalkeeper Laurie Walker with a fine strike after his first attempt had been blocked by his own team-mate Ben Baker.
The Poppies saw things out and will now take on the Steelmen at the home of Northampton Town on Tuesday, April 11.
Tom Lorraine became AFC Rushden & Diamonds’ all-time leading goalscorer but it wasn’t enough to prevent them exiting the Integro League Cup at the quarter-final stage.
Lorraine gave Diamonds the lead against Evo-Stik Northern Premier League Premier Division play-off contenders Buxton at the Dog & Duck when he converted a penalty for his 51st goal for the club.
But Danny Burns levelled before half-time and Buxton took the game away from the hosts with two goals in as many minutes when Brad Grayson scored from the spot and then added another soon after.
Nabil Shariff set up a tense finish by scoring the third penalty of the night but the visitors held on to secure a place in the semi-finals.
Diamonds return to the serious business of the race for the Division One South play-off places on Saturday when they host fellow contenders Leek Town.