The best overseas signings are ones with something to prove. And when one of those happens to be only the second Indian batter to score a Test triple hundred, consider yourself lucky.

Karun Nair is still only 31, a different man from the one who flayed England for an unbeaten 303 at Chennai at the back end of 2016. The batter, however, still has some of that precocious early magic left in him, as per the unbeaten 144 that takes Northamptonshire into Thursday on a healthy 351 for 9.

In turn, Surrey, for the first time this season, are glancing over their shoulders as Essex, 18 points behind, assumed a dominant position at home to Hampshire.

This 16th first-class hundred of Nair’s career, and first for the county, came off a patient 184 deliveries and carried a clear theme of rejuvenation for player and club. The start of a possible about-turn in a meandering career may trigger an unlikely about-turn in Division One’s relegation scrap.

You have to go back to February 2022 for Nair’s last three-figure score; 175 for Karnataka against Jammu & Kashmir in the Ranji Trophy. He has since left, joining Vidarbha, and speaking to ESPNcricinfo before this penultimate round of the Championship, relayed a desire to take some form back home with him. Having opened his three-game stint at Northants with 78 against Warwickshire, this knock against the best bowling attack in the division was a serene way of rediscovering one’s mojo.

The only points of malice came with No.11 Jack White, swinging wildly and occasionally nailing over midwicket and scything over backward point for six, amid the odd scuff for four. The 17th boundary, which took him to his hundred, was a gorgeous uppercut ramp in response to Surrey trying to prolong his stay in the nineties with short stuff.

Otherwise, an innings that began early on day one at 51 for 2, and will continue into a third day after rains washed out 63.1 overs on day two, was all about sound judgement. And though Surrey were able to take the three necessary wickets for a third bowling point, an engaging stand of 114 between Nair and Tom Taylor was a welcome shot of adrenaline.

Yet even with the three batting points – Northants had managed just four in the previous 12 matches – time out of the game is more damaging to the visitors than the hosts, adrift at the bottom by 32 points before their last two matches. It will take a lot of work to convert this into a second win of the season, especially with the defending County Champions desperate not to risk too much ahead of next week’s final round of games.

Nair’s availability for the run-in came about primarily through an existing UK visa following a stint for Burbage & ER Cricket Club earlier this summer. He was on a plane a week after a former manager sounded him out about replacing Sam Whiteman, who was returning to Australia. That he has picked up where the club’s leading scorer left off has been a boost, albeit one that perhaps should not have happened to this degree.

He was on 11 when Jamie Overton shelled him at second slip on Monday, and was dropped on Tuesday – with 131 to his name – when flaying to Ryan Patel at deep midwicket. The catch was taken initially, before the elbows hit the turf, dislodging the ball. It would, and should, have been 338 all out.

The worst drop, however, belonged to Cameron Steel, who not only shelled a regulation take a third slip that would have dismissed Taylor on 1, but may have cost Tom Lawes a second five-wicket haul of the season. Lawes, the pick of the quicks so far, had registered his fourth after dismissing Justin Broad with a thrilling bit of teamwork between Overton and Ben Foakes. The former scooped up an edge low to his left at second slip that the latter managed to clutch just above the ground with his right mitt.

Taylor, who is set to join Worcestershire on a three-year deal at the end of the season, was almost a shot a ball, chancing his arm from 193 for 7 with expansive drives and exactly the type of verve Surrey did not want. Nair relished the opportunity to coast, allowing Taylor to assume the dominant role, contributing 32 of the 50 stand, which came up in 57 deliveries. Taylor stung the fingertips of Steel at third once more with a full-blooded hack on 44, on his way to a second fifty of the season, and eighth of his career, off 55 deliveries. An inside edge past his stumps brought up the century stand from 115, with Taylor providing 59 of them.

If anything, Taylor’s demise after lunch only reinforced how wasteful Surrey had been. Overton pinned the right-hander on the pads seven balls after the lunch break, before hitting the top of Ben Sanderson’s off stump with the very next ball. Out walked Jack for the hat-trick ball, which was left precariously as it whistled full past off stump.

Nair then assumed the role of shepherd, ensuring the tailender only faced 15 of the 32 deliveries remaining in the day. The addition of 44 runs (and counting) for this final wicket was by no means crisp. Though Nair is off the back of 532 runs at a strike rate of 162.69 in the Maharaja Trophy, Karnataka’s T20 competition, he found the red Dukes ball harder to connect with, striking about one in three, much to the annoyance of the Surrey fielders. And Lawes of course, who ended up on the receiving end of both Nair’s sixes. Instead of five wickets, the 20-year-old is nursing 100 runs, with a delivery to go in his 23rd over.

The weather may yet make all this academic. But for now at least, Northants’ endeavour and Surrey’s profligacy gives both an evening wondering if the 2023 Division One season has one last twist in its tale at the top and bottom.