Karun Nair put Northamptonshire in a strong position to win their Vitality County Championship Division Two clash against Glamorgan with a majestic unbeaten double hundred.
The former India Test player hit 202 not out from 253 balls to help his side post a commanding 605 for 6 at Wantage Road, a first-innings total of 334. Nair shared a brisk sixth-wicket partnership of 212 with Saif Zaib, who scored his first ton of the season, as the pair plundered Glamorgan's bowling in support of Ricardo Vasconcelos' knock of 182.
The visitors struggled to 104 for 3 at stumps, still 230 all out, but could be rescued by Monday's forecast of persistent showers. Northamptonshire had only lost two wickets in more than two sessions of batting the day before. But their progress was soon slowed by a series of three dismissals.
Vasconcelos, resuming on 166 with the chance of a first-class double hundred in sight, missed out when Mir Hamza moved a ball just enough to have him caught behind. Brad Wheal looked shaky at first but settled into his rhythm and was rewarded when he edged back to George Bartlett, who was caught at the slips off a leading edge.
Glamorgan promptly replaced Wheal with James Harris - a move that paid immediate dividends as the seamer's second delivery trapped James Sales leg before to leave the home side five down for 82.
Zaib's arrival, however, gave the innings a new lease of life as he smashed Harris to the point boundary and edged Zain ul Hassan for four as Nair - who started the day on 55 - marched steadily towards his hundred.
The 32-year-old reached three figures when he edged Harris to long leg for two and then savaged Mason Crane, hitting the leg-spinner for successive fours and lifting him over the midwicket fence.
After cutting and sweeping with ruthless precision, Zaib was dropped by a reverse-sweeping Crane to Ul Hassan at backward point on 71 and began to fade as the 90s wore on.
Needing one for his century, Zaib was given another life when Colin Ingram dropped him at gully off Dan Douthwaite - and the left-hander took advantage, scooping a single before holed out to deep square leg in Crane's next over for exactly 100.
Nair continued to punish a subdued Glamorgan attack, hitting Wheal for a single to take him past 200 for the third time in his career. He was immediately dismissed by home skipper Luke Procter.
Northamptonshire's first-innings pair of Ben Sanderson and Chris Tremayne looked in good spirits when Billy Roots edged them both to the cover boundary.
The Northamptonshire openers had to wait until the second wicket to get the breakthrough when Northamptonshire teenage seamer Raphie Weatherall edged Ullah Hassan outside off stump.
Spinner Zaib, moving to the David Capel end, flicked one out of the rough to trap Root for 41 and Sam Northeast fell to Sanderson in the next over, caught by Emilio Gay's juggling in the slips.
Glamorgan's prospects almost deteriorated immediately when Ingram edged to Nair at first slip, but he and Kiran Carlson saw their side through to the close.