Northamptonshire 364 (Rossington 76, Berg 69) and 357 for 3 (Vasconcelos 185*, Keogh 126) beat Glamorgan 407 (Cooke 136, Lloyd 65, Carlson 54) and 311 for 5 declared (Selman 69, Carlson 59, Cooke 57*, Root 56) by seven wickets
Ricardo Vasconcelos and Rob Keogh conjured up centuries as Northamptonshire miraculously chased down 355 in 72.4 overs to beat Glamorgan by seven wickets in an LV= Insurance County Championship humdinger.
Vasconcelos and Keogh put on 239 for the third wicket, individually scoring 185 not out and 126, as Northants completed the third-highest successful fourth-innings chase in their history.
Glamorgan had given themselves 79 overs to bowl their hosts out on a pitch which had got flatter, having declared on 311 for 5 - after half-centuries from Nick Selman, Billy Root, Kiran Carlson and Chris Cooke.
But Vasconcelos lead the charge with his highest first-class score to tick off the runs with more than six overs to spare to hand Northants 23 points and their first win of the season, while Glamorgan remain winless.
Glamorgan boosted their lead from 248 to 354 runs in 70 minutes of aggressive batting from Cooke, Carlson and Callum Taylor. Cooke and Carlson set the tone with a 111-run stand in 122 balls as both reached half-centuries, in 62 and 69 balls, to go with their 136 and 54 respectively from the first innings.
Carlson departed when he was caught at deep third man, but Taylor joined Cooke to add 31 more runs in the face of defensive Northants bowling and fields before the declaration 40 minutes before lunch.
A mixture of attacking fields and intent from Vasconcelos, and to a lesser extent Ben Curran, meant that Northants flew out the blocks. The opening pair sped to 81 in 17.4 overs to open up the seemingly unlikely possibility of victory, with Vasconcelos reaching his half-century in 50 balls, via a tricky catching chance at second slip.
Curran was lbw to a nicely flighted delivery from spinner Taylor, before Charlie Thurston guided James Weighell to Andy Balbirnie at first slip.
But those wickets in successive overs proved to be a temporary stumbling block when Keogh joined Vasconcelos and the run-rate accelerated - 55 runs flowed in the following eight overs.
Keogh's fifty came up in 47 balls, shortly before Vasconcelos raised his bat and bowed to the dressing room after cutting Taylor to the point boundary - the 16th time he'd hit the ropes. It was the South African-born batter's seventh first-class century.
Keogh's eleventh career ton, and like Vasconcelos his second of the season, came in a spritely 109 balls with a powerful square drive.
The 200 stand and Vasconcelos' 150, brought up with a six over mid-on, were negotiated and met with a standing ovation from the players' balcony as the finishing line zoomed into sight.
Keogh edged David Lloyd behind with 34 runs still needed, but Luke Procter flicked off his legs to secure the win - a victory all the more impressive for Northants having been 76 for 5 in their first innings.