SOMEN Tchoyi completed a spectacular comeback and earned Albion a deserved draw at Old Trafford by crowning his full Barclays Premier League debut with his first Baggies goal.
United looked like comfortably extending their 100 per cent home start to the campaign as the Baggies gifted them a two-goal lead.
Javier Hernandez pounced on Scott Carson's poor parry five minutes into the game and an unfortunate slip by Nicky Shorey 20 minutes later enabled Nani to double the hosts' advantage.
But the battling Baggies stuck to their guns.
And after surviving Nemanja Vidic hitting the post early in the second half, Patrice Evra's 49th-minute own goal from Chris Brunt's free-kick gave them a lifeline.
Albion were in dreamland five minutes later as summer signing Tchoyi pounced on an Edwin Van der Sar mistake from another Brunt delivery to equalise.
The Baggies were full value for their 12th point of the season as they upset another of the Premier League's big guns after winning 3-2 at Arsenal on their last away trip.
Tchoyi was drafted into Roberto Di Matteo's starting XI as Marc-Antoine Fortune also earned a recall.
The men to make way were the benched Graham Dorrans and Peter Odemwingie, who lost his fitness race.
Wayne Rooney started on the bench for United as Sir Alex Ferguson opted for Hernandez and Dimitar Berbatov in attack.
Albion made a bright start as James Morrison ran from inside his own half and crossed to the back post where Brunt mistimed his header from ten yards, with just 55 seconds on the clock.
But the Baggies were punished in the fifth minute when a combination of Gabriel Tamas and Morrison felled Hernandez 25 yards from goal.
Carson could only parry Nani's low free-kick straight to the feet of Hernandez, who wasted little time in firing home from ten yards.
The visitors came close to levelling in the 13th minute when Morrison played Fortune in behind the United defence and he crossed low to the back post where Rafael da Silva made a goal-saving interception to deny Brunt a tap-in.
Seconds later, Berbatov sneaked in behind Gonzalo Jara and cut inside Tamas from the left before curling a right-foot shot just past the far post from the edge of the box.
On 20, Nani wriggled free to flash a ball just out of the reach of Hernandez in the six-yard box as the hosts continued to pressurise the Albion defence.
A minute later, Michael Carrick was allowed to centre from the right and Berbatov side-footed wide of the right-hand post when it seemed easier to hit the target from eight yards.
But Albion were certainly not wilting on the big stage and they managed to work the ball to Brunt in the middle in the 24th minute, who let fly with a long-range effort that sailed just past the left-hand post.
But seconds later, it was 2-0.
The unfortunate Shorey slipped on the wet surface to gift possession to Nani and the Portugal international raced forward before playing a one-two with Berbatov and firing home with his left foot.
But Albion regrouped and Rio Ferdinand almost put the ball into his own net on the half-hour mark as he struggled to deal with Shorey's left-wing cross at the near post.
Two minutes later, the Baggies worked the ball well and Brunt teed up Morrison, who curled a 25-yard shot just wide of the right-hand post.
The Red Devils were forced into a change as the half drew to a close, with Ryan Giggs limping off and Darron Gibson coming on.
Within two minutes of the restart, Nani had Jara twisting and turning and he stood the ball up for Vidic, who headed against the base of the left-hand post from ten yards
No-one knew it at the time, but that escape proved the game's turning point.
It was the Baggies who scored next, getting themselves back in the game in the 49th minute.
Tchoyi was hauled back by Anderson just outside the box on the right and, from the resulting free-kick, Brunt drilled a wicked low cross towards the near post where it deflected off Evra and past the despairing hand of Van der Sar on the goalline.
Incredibly, just five minutes later, Albion were level.
Brunt found space on the left and hooked a high cross into the box.
Under no pressure whatsoever, Van der Sar inexplicably spilled it to allow Tchoyi to tap into an empty net - and send the vocal away support into delirium.
Either side of the visitors' equaliser, Shorey was forced to make two last-ditch blocks, denying goalbound Berbatov shots on each occasion.
Di Matteo made a change in the 69th minute as Tchoyi made way for Jerome Thomas, who was making his comeback from a calf injury.
In the same minute, Carson saved Anderson's low drive and deserved the fortunate of seeing the ball hit Shorey and rebound back into his arms, with Hernandez lurking.
Ferguson made a double change with 20 minutes to go as Carrick and Anderson were replaced by Paul Scholes and Rooney respectively.
Referee Mike Jones produced a moment of controversy in the 79th minute when he awarded a free-kick to United in the Baggies penalty area for a supposed back-pass by Jara to Carson.
With the Albion wall encamped in their six-yard box, Nani squared for Rooney, whose goalbound drive was cleared just in front of the goalline&nbsp;by Tamas.
Far from settling for a point, the Baggies continued to search for a winner and, six minutes from time, Paul Scharner squared for Brunt who fired a right-foot shot just past the right-hand post from 20 yards.
And, in injury time, substitute Graham Dorrans went close again when he wriggled free on the edge of the box before testing Van der Sar with a low right-footed shot.
Albion negotiated four minutes of nerve-jangling stoppage time with little trouble to seal a famous point at the Theatre of Dreams.
UNITED (4-4-2): Van der Sar; da Silva, Ferdinand, Vidic, Evra; Nani, Carrick (Scholes 70), Anderson (Rooney 70), Giggs (Gibson 42); Hernandez, Berbatov. Subs not used: Kuszczak (gk), Smalling, O'Shea, Macheda.
ALBION (4-2-3-1): Carson; Jara, Tamas, Olsson, Shorey; Mulumbu, Scharner; Tchoyi (Thomas 69), Morrison (Dorrans 85), Brunt; Fortune (Bednar 77). Subs not used: Myhill (gk), Cox, Ibanez, Reid.
GOALS: UNITED - Hernandez (5), Nani (25). ALBION - Evra (og 49), Tchoyi (54).
BOOKINGS: UNITED - Gibson (foul 58). ALBION - Shorey (foul 39), Carson (kicking ball away 79).
REFEREE: M Jones (Cheshire).
ALBION STARMAN: James Morrison.
PIC: HE'S MY TCHOYI BOY...Fortune congratulates scorer Somen after his priceless equaliser
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