LONDON (AFP) - Arsenal squandered an opportunity to return to the Premier League summit after drawing 0-0 with Manchester United in an attritional game at the Emirates Stadium on Wednesday.
Both teams had suffered damaging results at the weekend, Arsenal crashing 5-1 at Liverpool and United drawing 2-2 at home to bottom club Fulham, and the tentativeness on either side made for a game of only sporadic excitement.
Robin van Persie came closest to scoring for United, spurning an excellent early chance and later hitting the crossbar with a header, while Arsenal centre-back Laurent Koscielny had a header cleared of the line.
Arsenal would have gone top with victory, but the draw left Arsene Wenger's side a point behind Chelsea in second place.
For United it was another missed opportunity to make up ground on the teams in the Champions League places, ahead of a mid-season trip to Dubai when they will gird their loins for a high-stakes run-in.
Former Arsenal striker Van Persie was playing at the Emirates for the second time as a United player and his old teammates gifted him a huge opportunity within seconds of kick-off.
Van Persie was allowed to creep up behind Mikel Arteta and steal possession from the Spaniard, but with only Wojciech Szczesny to beat he drove a tame shot into the Arsenal goalkeeper's arms.
In response, Jack Wilshere had a shot blocked by Chris Smalling after a weaving run, with Olivier Giroud heading over from the ensuing corner, while Tomas Rosicky saw a deflected shot saved by David de Gea.
With Antonio Valencia relacing Ashley Young for United, the champions deployed Juan Mata on the left flank, and the club's record signing teed up Van Persie with a pass down the inside-left channel, only for the Dutchman to shoot wastefully wide.
Giroud continued to best United captain Nemanja Vidic in the air, but he was unable to find the target with a succession of headers.
The French striker was also involved in a collision with Rafael da Silva that saw the United full-back land awkwardly on his neck. After soldiering on until half-time, the Brazilian gave way for Rio Ferdinand.
A war of attrition took hold early in the second period, with neither side able to fashion a chance as attacks foundered on imprecise passes and niggly fouls.
The home fans almost had something to shout about in the 62nd minute, but although Koscielny's glancing header from a right-wing corner beat the diving De Gea, Valencia was on hand to head the ball off the line.
Both managers made changes with 15 minutes remaining - Alex Oxlade-Chamberlain entering the fray for Arsenal and Adnan Januzaj taking Mata's place for United.
The game belatedly came to life in the closing stages, as both sides looked to snatch victory.
Giroud was unable to make telling contact with an inviting centre from Bacary Sagna, before Van Persie saw a header from a Wayne Rooney cross brilliantly turned onto the bar at the other end by Szczesny.
Arsenal midfielder Santi Cazorla had two late attempts to claim a winner, but on each occasion he was thwarted by Spanish countryman De Gea.