United were fortunate to win against a battling Wolves who equalised in the second half through substitute Sylvan Ebanks-Blake, cancelling out Park’s against the run of play effort on the stroke of half-time.
But deep into stoppage time, with United looking as they were going to drop two points, the South Korean scored to keep up the pressure on leaders Chelsea.
Owen Hargreaves saw his long-awaited return to action for last less than five minutes as he limped off with an apparent hamstring problem.
Bolton brought Champions League heroes Tottenham down to earth with a 4-2 victory after surviving a late scare at the Reebok Stadium.
The home side raced into a 3-0 lead thanks to two goals from Kevin Davies, one from the penalty spot, and Gretar Steinsson.
But Spurs hit back with Alan Hutton and substitute Roman Pavlyuchenko scoring in the last 11 minutes only for substitute Martin Petrov to seal Wanderers victory in stoppage time.
Bottom club West Ham were two goals to the good at Birmingham with a little over 30 minutes played, but the home side rallied to claim a point in a 2-2 draw at St Andrews.
Ten minutes later the visitor’s added a second taking advantage of some sloppy Blues defending. Valon Behrami made them pay.
Asamoah Gyan marked his first Premier League start for Sunderland with a brace in a controversial 2-0 win over Stoke.
The Ghana international took just nine minutes to open the scoring and the hosts then failed to double their advantage when Steed Malbranque failed to convert a penalty, as Asmir Begovic produced a superb save.
Stoke felt they had levelled midway through the second half when Lee Cattermole appeared to clear Kenwyne Jones's header behind his own goalline, but the referee Martin Atkinson only awarded a corner to the Potters.
Things got worse for Stoke when Ryan Shawcross was sent off for a bodycheck on Danny Welbeck on the edge of the penalty area.
The home side made the game safe four minutes from time when Gyan converted his shot from the edge of the box.
Neal Eardley gave Blackpool the lead after just 10 minutes with his first goal for the club.
However, the lead proved short-lived as Yakubu Aiyegbeni crossed for Tim Cahill to head past Matt Gilks.
David Vaughan restored Blackpool's lead three minutes into the second half, but again the Seasiders failed to hold onto their lead with the Toffees equalising for a second time two minutes later through former Blackpool loanee Seamus Coleman.
But imposing defender Brede Hangeland had other ideas scoring with the last attack of the game.
Blackburn Rovers climbed out of the bottom three with a 2-1 win over fellow strugglers Wigan at Ewood Park.
Rovers made the breakthrough just before the hour mark when Morten Gamst Pedersen curled a superb free-kick from way out on the right high into the net past Ali Al-Habsi.
The quality of the goal made up for the paucity of entertainment that had gone before.
The home side doubled their advantage on 67 minutes with former Latics striker Jason Roberts scored his first goal of the season.
Charles N'Zogbia gave Wigan hope 16 minutes from time when he too scored direct from a free kick leading the home side hanging on nervously for the final whistle.