Tries: Brown, Townsend
Cons: Townsend, Jones
Blues: (22) 41
Cardiff Blues crushed the Reivers at Netherdale to keep alive their hopes of claiming the Magners League crown.
Tries: Luveitasau (2), Shanklin (2), Penalty, Shellard (2)
Cons: N Robinson (3)
Borders had given them a fright by snatching the lead with two tries from Kelly Brown and Gregor Townsend.
The Blues made a storming start with early tries from Moses Luveitasau and Tom Shanklin before Reivers' fightback.
But Shanklin and then Luveitasau completed their brace before a penalty try and two Rhys Shellard scores made sure of a resounding Blues victory.
The Welshmen made a great start and it was no surprise when they surged ahead with a try after only five minutes.
A sequence of patient lead-up work which featured safe handling created the time and space for winger Luveitasau to glide over close to the corner. Nicky Robinson was wide with the conversion attempt.
The fired-up Blues stepped up their early momentum and stretched their lead when powerful Test centre Shanklin took full advantage of slack defence to plunge over.
This time Robinson was accurate with the kick, leaving the Reivers with a massive task to get back into the contest.
To the delight of the success-starved home fans, the Borders battled gamely and were rewarded midway through the half when Scotland breakaway forward Kelly Brown snapped up an opportunist touchdown.
Veteran stand-off Gregor Townsend added the extra points to set up a tense approach to the interval.
Even better was to come for the Reivers - and Townsend in particular - on the half-hour mark as he darted in for another slick score.
Replacement Steve Jones gleefully stroked over the conversion to give his team a shock lead.
The local joy did not last long, however, as Shanklin barged his way through to complete his double and swing the momentum back in favour of the visitors.
And there was another dose of gloom a minute before the break when the speedy Luveitasau also made it a brace of tries - making sure of the precious bonus point in the process.
Borders were dealt an added blow two minutes after the restart as skipper Chris Cusiter went off with ankle problem, though it did not look serious.
The Blues turned on the power in the final quarter to add a penalty try and two Rhys Shellard scores - along with two Robinson goals.
Borders: Moffatt; Flockhart, Law, Rennie, De Luca; Townsend, C. Cusiter (capt), Kerr; Ford, Kalman, Grimes, Hamilton, Palepoi, Dalziel, Brown.
Replacements: Jones for Law (24), Chrystie for C. Cusiter (42), Scott for Ford (59), Douglas for Kalman (56), Miller for Palepoi (50), Gray for Dalziel (56).
Not Used: Vernon.
Cardiff Blues: Macleod; R. Williams, J. Robinson, Shanklin (capt), Luveitasau; N. Robinson, Fairhurst; Jenkins, R. Thomas, G. Powell, Jones, Morgan, Lewis, Rush, Sowden-Taylor.
Replacements: Riley for Macleod (39), Phillips for Fairhurst (64), G. Williams for R. Thomas (55), Davies for Jones (59), Shellard for Sowden-Taylor (72).
Not Used: Roberts, Hewitt.
Ref: A Rolland (Ireland).