Ben Cohen scored two tries for Northampton
Border Reivers: (12) 19
Tries: Ford, Danielli, MacRae
Cons: MacRae 2
Northampton: (17) 29
Tries: Tupai, Diggin, Cohen 2
Cons: Spencer 3
Northampton kept on course for a place in the knock-out stages of the Heineken Cup with a bonus-point victory over Border Reivers at Murrayfield.
Reivers grabbed the lead in the seventh minute through hooker Ross Ford's try after a line-out.
Saints' Paul Tupai then crossed only for Simon Danielli to intercept 80m out and restore Reivers' lead.
Paul Diggin struck for Saints before half-time and two Ben Cohen tries soon after half-time made the game safe.
Captain Calum MacRae, who also kicked two conversions, scored a late try for Borders to bring the gap down but the result of the match was already beyond doubt.
The match had been switched to Murrayfield after the pitch at the Reivers' normal home of Netherdale was deemed unplayable because of heavy rain.
Northampton face group leaders Biarritz at Franklins Gardens next weekend in the showdown to decide who will progress as group winners.
Northampton coach Paul Grayson:
"I was more than prepared to play - wherever the game was to be. It was entirely up to the referee (George Clancy).
"I was particularly delighted with the performance of Ben Cohen at centre. In addition to his two tries, he put in a power of work."
Borders coach Steve Bates:
"I don't know why the match was switched. I have played in conditions far worse than the ones at Netherdale.
"The whole business obviously upset our preparations and we lost some advantage through not playing at home.
"I was surprised at the decision of the referee. We had had people with expertise working on the pitch.
"During the game we showed we are not that far away from teams like Northampton."
Border Reivers: MacRae (capt); Danielli, De Luca, Rennie, Daniel; Townsend, Chrystie; Kerr, Ford, Douglas, Grimes, Palepoi, Newlands, Miller, Brown.
Replacements: Scott, Kalman, Dalziel, Vernon, McKerchar, S Jones, Robertson
Northampton Saints: Diggin; Sean Lamont, Cohen, Kydd, Howard; Spencer, Robinson; Smith, Thompson (capt), Barnard, Gerard, Short, Tupai, Fox, Browne.
Replacements: Hartley, Budgen, Lord, Easter, Lewitt, Laird, Wyles.