The victors played above themselves, inspired by standout Eric Elwood.
The sides had met last season before in this competition where Northampton had won 31-11 at Galway. The hosts had seven survivors while Northampton had four in their line-up. Northampton started well and, within 80 seconds, had a penalty 32 metres out from the Connacht posts, but the stand-off Alastair Hepher missed.
Connacht took the lead three minutes later with a penalty by Elwood from the visitors' 22. The pressure from the Irish side continued and, in the 10th minute, they extended their lead when Elwood fed the ball to the centre Pat Duignan, who burst through and touched down for a try under the posts, Elwood added the conversion.
The hosts' momentum kept going and, in the 24th minute, the ball was fed to the open side flanker Shane McEntee, who went over, Elwood converting for a 17-0 lead. Connacht's final score before the interval came on 28 minutes when Elwood had another penalty.
Hepher scored the first three points for Northampton in the 35th minute with a penalty 16 metres from the Connacht posts to make it 20-3 at half- time. The lead was pegged back in the 47th minute when Hepher scored a penalty, but Elwood turned the screw with two more penalties.
The winners' Mervyn Murphy took over kicking duties in the 75th minute from Elwood, who went off injured, and increased the lead, but four minutes later Connacht gave away a simple try to Nick Beal. Hepher converted.
The final points was a try three minutes into injury time by Nigel Carolan, with Simon Allnutt added the conversion.
Connacht: Tries Duignan, McEntee, Ruane, Carolan. Conversions Elwood 3, Allnutt 1. Penalties Elwood 4, Murphy 1. Northampton: Tries Beal 1. Conversions Hepher 1. Penalties Hepher 2.
CONNACHT: W Ruane (Ballina); N Barry (Clontarf), P Duignan, M Murphy, N Carolan; E Elwood (all Galwegians), C McGuiness (St Marys College); J Maher (Bective Rangers), B Mulcahy (Skerries), M Finlay (Galwegians), M McConnell (Buccaneers), G Heaslip (Galwegians), R Rogers (Blackrock College, capt), B Gavin (Galwegians), S McEntee (Wanderers). Replacements: R Southam (Suttonians) for Barry, 74; S Allnutt (Corinthians) for Elwood, 74; R Ward (Old Belvedere) for Maher, 77; M Cahill (Bohemians) for Finlay, 82; M Reilly (St Marys College) for Gavin, 82.
Northampton: I Hunter (N Beal, 57); C Moir (G Townsend, 57), A Blyth, M Allen, H Thorneycroft; A Hepher, D Malone; M Hynes (C Allen, 69), C Johnson (A Clarke, 69), M Stewart, J Chandler, M Bayfield (capt; S Foale, 49), D Mackinnon, S Tatupu, B Pountney.
Referee: G Borreani (Fr).Reuse content