Didier Drogba celebrated his return to Premier League duty with a first half equalizer at the KC Stadium to cancel out Stephen Mouyokolo's earlier effort on a frustrating night for Carlo Ancelotti's Chelsea. Drogba struck his 20th goal of the season on 43 minutes to haul the Premier League leader level after defender Mouyokolo had headed Phil Brown's Hull City side into a surprise lead with his first ever goal for the top flight struggler. But despite Drogba coming to the rescue it wasn't enough to help Chelsea secure the win it so badly needed to restore its four-point advantage over Manchester United at the top of the table. The London club now has a lead of just two points and United manager Sir Alex Ferguson will be thankful to Hull for holding his great rival to a draw to blow the title race wide open. Ancelotti had the luxury of recalling Drogba for the first time since he departed for the African Cup of Nations over four weeks ago, while England internationals Joe Cole and Ashley Cole had to be content with a place on the bench. John Terry also maintained his place in the side despite the on-going pressure on him to resign as England captain following his off-field problems while Deco was recalled to the starting line-up. Brown, meanwhile, made just one change to the side which was held to a disappointing draw with Wolves last weekend, recalling Craig Fagan on the right wing in place of Bernard Mendy. The Hull manager resisted the temptation to hand a full debut to new loan signing Amr Zaki. Hull had gone nine games without a victory and found itself entrenched in the relegation zone. Considering Manchester City was the next visitor to the KC Stadium then the immediate future looked bleak. But Chelsea struggled to find its rhythm from the start and seemed to make Hull's evening easier than expected. Frank Lampard worried Boaz Myhill with a swerving drive inside nine minutes which the Hull goalkeeper could only palm straight to Nicolas Anelka but the French striker stubbed his shot badly wide with the goal at his mercy. It wasn't until the 24th minute that Chelsea threatened again when Branislav Ivanovic sent over an inch-perfect cross for the waiting Michael Ballack but all the German midfielder could do was power his diving header straight at Myhill from close range. The longer the game went on the more Hull seemed to grow in confidence but it still came a surprise when it took the lead with its first real attack of the game. Terry was nowhere to be seen as Stephen Hunt swung over a corner and Mouyokolo rose the highest to head past the helpless Petr Cech. But Hull's lead always looked fragile and it lasted just 13 minutes before Drogba levelled the scores with a powerful free kick into the bottom corner of Myhill's goal. Sunderland failed to halt its slide towards the relegation quagmire after Stoke claimed a deserved point in an uninspiring goalless stalemate Monday. The draw means Steve Bruce's side, which started the season in such promising fashion, has now won only once in its last 14 league matches and it is just four points above the bottom three. Notts stuns Wigan Notts County produced an FA Cup replay shock with a 2-0 win at Premier League Wigan Athletic Tuesday to earn a place in the fifth round. The League Two (fourth division) side bridged a gap of 59 positions in English football's standings to stun Wigan with a Stephen Hunt header and an own goal by Gary Caldwell – both goals coming in three minutes in the second half. Another fourth round replay also produced a shock with Championship (second division) Crystal Palace, who was recently plunged into a relegation dogfight after a 10-point deduction for going into administration, ousted top flight Wolverhampton Wanderers 3-1 at Selhurst Park. Danny Butterfield netted a second-half hat trick for Palace who will take on Aston Villa for a place in the quarterfinals. Notts County's reward for its victory over Wigan is another crack at Premier League opposition Fulham.