Jamie Mackie put QPR ahead at Old Trafford, where Redknapp was watching from the stands hours after replacing the fired Mark Hughes.
But the west London team failed to secure its first win of the season, with Jonny Evans equalizing before Darren Fletcher and Javier Hernandez scored to put United back on the winning path after losing at Norwich last weekend.
"We played for 10 or 15 minutes," United manager Alex Ferguson said. "That was the sum total of our real performance from Manchester United. Of course it is frustrating we keep ending up in that position but when they scored it definitely sparked us up."
United is now two points ahead of Manchester City, but the defending champions are at Chelsea on Sunday.
West Bromwich Albion dislodged Chelsea from third by keeping up its flying start to the season with a 4-2 victory at Sunderland, but Arsenal is languishing in sixth place after a 0-0 draw with Aston Villa.
At Old Trafford, United halted a run of back-to-back losses, but like so often this season had to fight back from a losing position.
Seven minutes into the second half, Anders Lindegaard turned Kieron Dyer's low cross away from his goal and Mackie put the ball into the net from close range.
"It's not great," Fletcher said. "The only positive is we keep coming back — we cannot allow it to keep happening."
The game turned in United's favour only after Paul Scholes and Ashley Young were replaced by Anderson and Javier Hernandez.
It was defender Jonny Evans, though, who equalized. The Northern Ireland international nodded Danny Welbeck's header from Wayne Rooney's corner into the net in the 64th to claim his third goal of the season.
Four minutes later, Fletcher scored his first league goal since recovering from a chronic bowel complaint that threatened his career, heading in another corner from Rooney.
Hernandez claimed his ninth of the season before United defender Rafael da Silva cleared Clint Hill's header off the line.
"I would tell the fans: 'Don't lose faith'," said QPR coach Mark Bowen, who temporarily took charge of the team as Redknapp watched from the directors' box. "The quality is there but everything is conspiring against us at the moment. It's individual errors which are costing us rather than team errors."
While QPR believes it is underperforming, West Brom is exceeding expectations, sitting just four points behind United after a fourth consecutive win.
Zoltan Gera put West Brom ahead in the 30th and, after Simon Mignolet fumbled Chris Brunt's bouncing throughball, Shane Long put the ball into the empty net.
Although Craig Gardner pulled one back for Sunderland from a free kick, Romelu Lukaku restored West Brom's two-goal cushion from the penalty spot after Adam Johnson tripped Liam Ridgewell.
Again Sunderland tried to mount a fightback when Stephane Sessegnon scored, but Marc-Antoine Fortune's neat finish in stoppage time put West Brom's win beyond doubt.
"We have had a lot of plaudits and the players deserve it because so far, we have been a really good team," West Brom manager Steve Clarke said. "But you don't get carried away in the Premier League. We are still this side of Christmas, there are a lot of games to be played, a lot of points to be fought for."
Everton is three points adrift of fourth-place Chelsea after being held to a 1-1 draw by Norwich.
Steven Naismith's first-half opener for the Toffees was cancelled out in the 90th when Sebastien Bassong headed past goalkeeper Tim Howard.
Wigan moved five points clear of the drop zone as Jordi Gomez's hat trick secured a 3-2 victory over struggling Reading, which had led through Sean Morrison's first-half goal.
After Gomez's first goal after the break, Reading drew level with a howler from Wigan goalkeeper Ali Al Habsi.
Hal Robson-Kanu's shot deflected off Wigan midfielder David Jones and bounced high in the air. Standing by the goal line, Al Habsi jumped and tipped the ball off the bottom of the crossbar. It rebounded off the goalkeeper and into the net, but Jordi Gomez scored his third goal of the game in the second minute of stoppage time.
At the Britannia Stadium, Charlie Adam scored his second goal of the season for 11th-place Stoke in a 1-0 victory over Fulham.