The champions seemed set to continue their excellent home record over Wigan – who had not won here since 2012 – before they were floored in a dramatic, late finish.
In what had largely been a scrappy encounter, Leeds led through Tom Briscoe’s 22nd-minute converted try and went 8-0 ahead when Kallum Watkins slotted a penalty just after the hour mark.
In fairness their fine defence never truly looked like being breached until Oliver Gildart finally got over in the 71st minute.
Tomkins converted and it sparked the Cherry and Whites into life.
Ryan Sutton burst clear from the restart and Ashton Golding was needed to produce a desperate tackle to deny Gildart again, George Williams unable to pick up the forced pass inside.
Wigan would not be denied and when Brett Delaney caught Sam Powell high four minutes from time, full-back Tomkins levelled.
The world’s costliest player was not done, though.
In the next set Wigan managed to just get inside Leeds’s half and the 29-year-old somehow slotted a difficult angled drop-goal from almost 40 out.
The visitors – who denied Leeds the chance to overhaul them in second spot – saw the restart bounce into touch to give Brian McDermott’s side a chance to respond.
However, Joel Moon’s drop-goal effort was charged down and then, agonisingly, Richie Myler’s attempt fell wide.
Tomkins will have loved managing to turn this game in his side’s favour.
He had started the game well defensively showing great positional sense to clean up a couple of threatening Leeds kicks.
On attack, however, he was less decisive. Twice in the first half he dropped simple passes in the Rhinos’ 20 to waste clear attacking opportunities and ensure the hosts went in having kept their line in tact.
The South Stand has historically never suffered fools gladly and, even still in its part-built state, the Leeds fans showed that it will continue that mantra.
They quickly started up a chant of ‘That’s why they’re selling you’ with reference to Tomkins’s reported move to Catalans Dragons in 2019.
When Wigan fans started laughing, too, he must have thought the time to move was now. However, they were not ridiculing their own player. A male streaker had entered the field of play – saying something, perhaps, about the first-half fare that it seemed the most entertained the crowd had been all night.
He had been jogging around in backplay for the best part of a minute before anyone seemed willing to do anything.
As the hooter sounded for half-time he was eventually ushered off with a humorous interjection from the PA announcer, who referred to just how cold it was at Headingley.
Leeds were not laughing by the end, though, and they will be wishing they had gone for the jugular when in control.
Wigan were reduced to 12 men after Sam Powell was yellow-carded for a ‘crusher’ tackle on Ashton Golding in the 43rd minute.
Leeds had an immediate chance to capitalise when – from a standing start – captain Watkins suddenly accelerated through a gap 20m out.
The England centre, who signed a new deal until the end of 2021 this week, set up Myler perfectly with his pass, but the scrum-half somehow spilled between the posts.
Thereafter Wigan managed to negotiate the 10 minutes well and, indeed, created more pressure themselves by kicking intelligently.
When Powell did return space opened up for Joel Tomkins, but he was brilliantly hauled down by Myler just as it seemed certain he would score.
Sam Tomkins’s grubber caused some mild panic in the Leeds ranks, but, as they did most of the night, they scrambled well, this time Golding just getting across to knock the ball dead.
It was the third drop-out conceded by them in that half, but, crucially, Wigan captain Sean O’Loughlin ushered a needless forward pass in the next set so the pressure was released.
Soon after Dan Sarginson – the former England centre who had a poor night for Wigan – conceded a soft penalty and Watkins curled over a difficult goal to extend the lead to 8-0.
Even though there were still 17 minutes left to play, in the circumstances it seemed it might be enough to seal the victory. It was not.
Second-row Stevie Ward, in his 100th Super League game, was industrious as ever for Leeds, coming up with one timely tackle on Joe Burgess.
But there was plenty of sterling efforts in the Leeds pack, which was instantly augmented by the return of prop Adam Cuthbertson, playing his first game since breaking a hand in February’s World Club Challenge defeat in Melbourne.
Matt Parcell, too, thrived at hooker, but McDermott’s side – who head to Hull FC next Thursday – will rue that missed opportunity to turn the screw, gifting Wigan a way back in.
Leeds Rhinos: Golding; Briscoe, Watkins, Handley, Hall; Moon, Myler; Delaney, Parcell, SIngleton, Ablett, Ward, Jones-Buchanan. Substitutes: Cuthbertson, Oledzki, Mullally, Smith.
Wigan Warriors: S Tomkins; Marshall, Bateman, Gildart, Burgess; Williams, Powell; Clubb, Leuluai, Navarrete, Isa, Farrell, O’Loughlin. Substitutes: Sutton, Tautai, J Tomkins, Sarginson.
Referee: Ben Thaler (Wakefield)