Meanwhile, Scott Wootton’s own goal cost Leeds a spot in the quarter finals
An eventful day in the FA Cup saw Paul McShane score his first goal in the competition in nine years, Arsenal held by the heroics of Hull City goalkeeper, Eldin Jakupovic, and Scott Wootton turn the ball into his own net to end Leeds United's campaign.
The last thing Arsene Wenger needed was another fixture in the run in to secure a first Premier League title in over a decade. Add to this the prospect of facing Barcelona in the Champions League, today's result will prove all the more frustrating.
Their next four fixtures read Barcelona (H), Manchester United (A), Swansea (H) and Tottenham (A) before the replay at the KC Stadium will likely take place on Monday March 7.
Wenger's side did have chances to put the game to bed, Welbeck's first half header was aimed directly at the keeper and Walcott's shot from a tight angle was well-saved by Jakupovic.
Mike Dean refused to give Arsenal a penalty in the opening minutes, despite the replay showing that the ball did strike Alex Bruce on the arm.
The second half produced more of the same, Jakupovic produced a number of fine saves before Olivier Giroud and Alexis Sanchez were introduced.
Neither could break the deadlock and as fate would have it, Hull's Sone Aluko would go on to squander the best chance of the game when his volley was struck straight at David Ospina.
Both sides will go again and Steve Bruce will fancy their chances considering Arsenal's run-in over the coming weeks.
Arsenal were left frustrated this afternoon at the Emirates Stadium. Image: Jonathan Brady / PA Wire/Press Association Images
Reading 3-1 West Brom
The result has been overshadowed by an incident after the game, when a coin was thrown at West Brom player Chris Brunt as he attempted to give his shirt to a fan.
“I was walking towards our supporters at the end, and they thought it was okay to throw a coin at their own players. I’m disgusted,” Brunt told BBC Sport.
“If they want to come forward and say they don’t like what they’ve seen then that’s fine. Fans are frustrated we were 1-0 up and lost.
“They paid a lot of money to come, but a small minority spoilt it. There were young kids there. I was absolutely disgusted and ashamed.”
“I’ve still got the 50-pence coin. I spotted a little girl in the front row and wanted to give her my shirt.
"There’s absolutely no excuse for that and no place for it in football. I’ve been here a long time and I’ve loved my time here and that’s the first time I’ve been ashamed of our supporters.
“I hope whoever’s on the way home who thought it was alright to throw coins at their own team has a good look a themselves. They know where I am during the week and if they want to come and have a discussion with me, that’s not a problem.
“I’m a big lad, I can take it no worries.”
The deplorable act comes after goals from Paul McShane, Michael Hector and Lucas Piazon granted Reading safe passage into the quarter final of the FA Cup.
West Bromwich Albion fans voice their anger towards Chris Brunt after the coin-throwing incident. Image: Scott Heavey / PA Wire/Press Association Images
Watford 1-0 Leeds United
Scott Wootton's shocking own-goal allowed made it there fourth game in all competitions without a win and allowed Watford to continue their excellent run in the competition.
Watford hardly looked threatening in the opening stages, but dominated possession as they began to control the game.
It was a Ben Watson cross that Wootton turned into his own net and leave Leeds with nothing to show for an afternoon of hard graft.
Scott Wootton OG is one tidily shanked finish https://t.co/3TNoE3Iw56— James Dart (@James_Dart) February 20, 2016