Royal performance shocks West Brom
The Baggies had been in cruise control after Belgian international striker Romelu Lukaku had put them 2-0 up and hit the woodwork twice.
Reading seemed down and out. A return to the bottom of the table, after QPR's draw with Tottenham earlier in the day, seemed inevitable.
But Jimmy Kebe grabbed an opportunist goal to set up a tense finish and the Royals snatched victory from the jaws of defeat by completing a dramatic late turnaround.
Le Fondre came off the bench to draw Reading level with an 88th minute penalty after Kebe had been fouled by Jonas Olsson before Pogrebnyak bundled in the winner from an Ian Harte free-kick.
Reading had been hoping their 3-1 FA Cup win at Crawley would kick-start their survival bid and they started with new signing Daniel Carrico in central midfield.
But for 80 minutes they seemed destined for another Premier League defeat - and a return to the foot of the table as Lukaku and James Morrison led them a merry dance.
Reading goalkeeper Adam Federici pulled off a sharp save to deny Morrison, who had been picked out by Jerome Thomas after a dangerous West Brom counter-attack.
If that had served as a warning then Reading did not heed it as West Brom cut them open with ease to take the lead.
Lukaku, on loan from Chelsea until the end of the season, released Morrison down the left and then received the return ball to beat Federici from six yards out.
Reading sought a positive response. Harte released Kebe down the right and he drove in an inviting cross but Pogrebnyak opted not to attack the six-yard box.
When Chris Gunter worked some space down the same flank he floated a cross in for Jobi McAnuff but the Reading captain could not generate any power and Foster claimed his soft header.
Reading struggled to retain composure and clear their lines as West Brom, with Morrison a constant danger, began to crank up the pressure.
When Carrico did released Kebe on the counter-attack, his first touch as he entered the West Brom box was so poor that the covering defender cleared for a throw-in.
Reading were booed off at half-time and fortunate not to go further behind immediately after the restart, when Harte sloppily conceded possession and Lukaku almost doubled his tally.
Chris Brunt preserved West Brom's lead with a last-gasp block to deny Garath McLeary after Foster had missed Kebe's cross from the right.
West Brom manager Steve Clarke said this week that Lukaku had the ability to ``frighten'' defenders - and the Belgian was beginning to cause havoc for Reading.
Lukaku had one strike chalked off for offside before he hit the post with a glancing header after Morrison's excellent run and cross down the left.
West Brom's success down that flank highlighted why Reading this week signed the Republic of Ireland right-back Stephen Kelly, who was watching from the stands.
Lukaku then rattled the crossbar with a thundering left-foot strike off the bar before finally hitting the target again, drilling a low shot past Federici.
The Baggies had launched a counter-attack from their own box. Morrison fed Lukaku and the teenager cut in from the right, stepped inside Adrian Mariappa and then beat Federici at his near post.
There seemed no way back for Reading but with 10 minutes left Kebe snuck in at the back post to meet McCleary's cross and beat Foster with a low header.
Reading began to press hard and, with two minutes remaining, Kebe was clattered by Olsson on the edge of the West Brom box.
Le Fondre, who blasted a penalty in the FA Cup win against Crawley, this time tucked it away calmly to Foster's left.
And an incredible comeback was completed when Harte launched a free-kick into the box, Alex Pearce knocked it down and Pogrebnyak bundled the ball past Foster.