Semi Ajayi went from hero to villain as his second-half own goal cancelled out his opener as Leeds held West Brom to a 1-1 draw at The Hawthorns.
The Baggies got off to the perfect start in the top-of-the-table Sky Bet Championship clash as centre-back Ajayi, with the help of goal-line technology, hooked the hosts into a second-minute lead.
But the introduction of Patrick Bamford at half-time inspired the Leeds comeback as his header, seven minutes after coming off the bench, deflected in off the unfortunate Ajayi.
The draw ensures Leeds remain top of the Sky Bet Championship ahead of West Brom on goal difference, with the top two now nine points clear of the chasing pack in the race for promotion.
How Leeds recovered to stay top
A raucous Hawthorns crowd got the start they craved just two minutes into the New Year's Day clash.
After Kiko Casilla failed to deal with a corner, Ajayi exchanged headers in the box with Kyle Bartley before looping a shot that was judged to have crossed the line despite Jack Harrison's attempt to hook it clear.
West Brom failed to push on from securing the early lead and allowed Leeds to steadily grow into the game, though the visitors failed to register any clear-cut attempts on goal.
The hosts thought they should have had a penalty on 24 minutes when Romaine Sawyers appeared to be hauled to the ground in the area by Mateusz Klich, but referee Robert Jones was unmoved.
Despite Leeds' improvement, it was West Brom who should have scored before the break. Hal Robson-Kanu slipped Matt Phillips through on goal a minute before half-time, but with just Casilla to beat the winger fired straight at the goalkeeper.
Marcelo Bielsa introduced Bamford and Barry Douglas during the interval and the substitutions yielded an immediate reward as Bamford headed Harrison's cross towards goal and deflection off Ajayi took is past Baggies goalkeeper Sam Johnstone on 52 minutes.
West Brom looked to wrestle back the initiative but found Casilla in inspired form as he thwarted a Matheus Pereira free-kick before stoping substitute Kyle Edwards' drive as both sides had to settle for a share of the spoils.
What the managers said…
West Brom manager Slaven Bilic: "We should be proud. It wasn't a beautiful game, but it was a very intense one with a lot of set-pieces. We created more than enough chances, we started great but sometimes when you go in front you take a step and try to shore things up. Leeds had the ball but we coped with that and we had a great chance to go two up before half-time. But it was a fair result."
Leeds head coach Marcelo Bielsa: "We should have won the match, but we could have won the match. Bamford took advantage of the battles and fights. He is a player with more physical resources for this kind of match."
Man of the Match - Stuart Dallas
What's next?
The third round of the FA Cup sees West Brom travel to Charlton on Sunday at 2.01pm while Leeds head to Arsenal on Monday at 7.56pm.