"I knew you'd win," says James.
I'm glad he didn't mention that beforehand.
It's 4pm on a warm sunny Sunday and the aches are beginning to make themselves felt as the adrenalin drains away. I'm nursing a couple of blisters; we're both chugging back lukewarm mineral water as if it's about to be made illegal.
But I'm a happy bunny. It's one of those rare days in rental karting - in any racing - when everything goes right. After sixteen months of exile and four months of learning new circuits in the BRKC, it's great to be back at one of my favourite haunts.
Thruxton is a good 'un. It's expensive, but the karts are fast and biddable and the circuit is world class. 1086 metres, twelve corners, not a moment's rest. It's a challenging, demanding place - and wonderfully rewarding when you get it right. Deep in the Hampshire countryside, with the car circuit and airfield just a couple of hundred metres away, there's a sense of occasion about every visit.
It's also friendly, generally well-organised and suffers fewer kart gremlins than many other circuits. In fact, I have only one complaint, and it's the same every time I visit on a Grand Prix Sunday. There's a bloody great plasma screen on the wall, which invariably is showing the Grand Prix live, exactly when I least want to see it. The mentality is a stark contrast from the BRKC - when one of the rounds coincided with a Grand Prix, there was a TV/radio blackout and anyone who did hear the result was under strict orders not to mention it.
Wind back three hours. I'm in the queue to sign in, trying to avoid the screen where the Hungarian Grand Prix has just started. I'm seething at having the race spoiled, but deep inside is a tiny grin: I've glimpsed that it's wet at the Hungaroring. Go Jenson, I think.
I change outside and manage to avoid hearing any more about the Grand Prix; twenty minutes later I've forgotten about it entirely, as I attempt to reaquaint myself with the circuit in a ten-minute qualifying session. Some days I wonder if Thruxton is more thrilling even than Daytona. Certainly the karts are more responsive. They suit my precise style well, but are edgier, more punishing of clumsiness. The main aim today is to work on my consistency in preparation for the British 24 Hours at Teesside in four weeks' time; after such a long gap away from Thruxton I have no preconceptions about my competitiveness.
I'm pleasantly surprised to qualify in pole position. A quick scan of the timing screen reveals four of us covered by three tenths of a second, with long-time endurance teammate James back in sixth. I've got a fight on my hands, and the butterflies begin to flutter.
I'm a little tardy away from the lights and lose a place to the driver in second, who looks exactly like the Stig. I slot safely into second but struggle badly with front-end grip for the first two laps. Stig seems not to have the same problems, and quickly pulls out a three-second lead.
And there, for the next thirty laps, I stay. Stig and I quickly drop the chasing pack; his lead varies from two to four seconds. I'm driving well, but so is he: we're trading fastest laps. At fifteen laps we begin to lap backmarkers; this gets progressively harder as we work our way through the field. I'd forgotten how difficult it is to overtake here and struggle with a couple of the faster karts: there's room for improvement in this area.
But Stig has his own problems, and I keep him in sight, keep the pressure on. With 37 of our 45 minutes gone, I'm less than two seconds behind. But we're running out of laps and my hopes of catching him are fading-
And then it comes: too impatient with a backmarker who hasn't seen him, he's pushed wide at the fast chicane, spinning onto the grass, and I'm through into the lead.
But the celebrations will have to wait. He's only a few seconds back, and I've got a train of backmarkers to clear: one slip will turn the tables again.
Sixty seconds ago I was willing the race to continue. Now I'm willing it to end. With 40 minutes gone I encounter James near the head of the train of backmarkers; in a hurry to pass, I rap him lightly, lift a hand in apology and hope I haven't hurt his race.
The last few laps are tidy, and I take the flag with a mixture of relief and delight. I was a little lucky, but know I've driven well; the constant pressure forced Stig's error. My body has held up well to nearly an hour of punishment aside from my right hand, which again has blistered. I'll have to take steps against a repeat at Teesside.
James has finished a resigned ninth, a lap down; an accomplished Caterham racer, his car-honed style means he can struggle to adapt to the vagaries of rental kart handling. But he's enjoyed his on-track battles and is reasonably satisfied with his pace. We part with plans to race again in the autumn, and I head home to catch up with events in Hungary.
Three hours later I'm cheering one of my favourite drivers across the line, and raising a glass to a fine day of motorsport. A win for me and a win for Jenson Button.
And just twenty-six days until I turn a wheel in anger at Teesside. Watch this space...