Full time: Manchester United 1-2 Arsenal
Full time: Manchester United 1-2 Arsenal
Game over at Old Trafford. Arsenal become the second team through to the last four. With that over, head over to our live blog for the semi-final draw.
Arsenal should have it won with a stunning break as Ozil, cuts the ball back to Sanchez and De Gea makes a fine save to keep United in the cup, barely.
Into five added minutes at Old Trafford.
Another United player goes to ground and another yellow card for simulation from Michael Oliver. Adnan Januzaj is the guilty party and it's a horribly delayed stumble to the flood in the penalty area. Great decision.
Lots of credit going the way of Michael Oliver following his dismissal of Angel di Maria. Less than seven minutes of normal time left at Old Trafford and United pushing for an equaliser.
Red card: Angel di Maria (Manchester United)
It goes from bad to worse for United as record signing Di Maria is sent off for the home side after first being booked for diving and then getting a second straight away for pulling the referee Michael Olivier's shirt. That might be that.
Change for Arsenal too as Danny Welbeck is replaced by Olivier Giroud. Has the ex-United man come back to haunt his old club? Cazorla should finish the tie but De Gea makes a fine save to his left.
Alexis Sanchez wins and takes a free-kick from the right corner of the penalty area but De Gea makes a good low save. Adnan Januzaj coming on for the home team now, with Marcos Rojo off.
All United since the goal and they go close again as Young's back post cross finds Fellaini, but Szczesny is equal to his downward header.
Chance for United with 25 minutes remaining. Michael Carrick flicks on a left-sided corner and Smalling sticks out a leg and diverts the ball over the bar.
Hector Bellerin perhaps fortunate to still be on the pitch and Ashley Young skips inside him and is taken down by the youngster. Already booked, referee Olivier decides against a second caution.
Goal: Manchester United 1-2 Arsenal (Danny Welbeck)
Arsenal back in front at Old Trafford and it's the former United man Danny Welbeck with the goal. Antonio Valencia plays a horrid backpass which is short of De Gea and Welbeck nips in, beats the United 'keeper to the ball and slots into an empty net.
Now Ashley Young enters the referee's book as he takes down Danny Welbeck. Plenty of flow lost from this game compared with the opening 45 minutes. Both managers have taken the string out of the game. as I write that Angel di Maria is put through by Fellaini but he shoots wide.
Yellow card for Marouane Fellaini after a succession of fouls, two in a row, in this second half. Michael Olivier has no hesitation. Scrappy game at the moment with an hour played. Will we get a winner?
Arsenal really should be back in front. Chris Smalling miss-controls the ball straight at the feet of Cazorla, who finds Sanchez but his shot is deflected into the arms of De Gea.
Problem for Alex Oxlade-Chamberlain who has pulled up with a hamstring problem after pulling out a challenge with Marcos Rojo. That will spark a change for the Gunners with Aaron Ramsey coming on. Half chance for United as Wayne Rooney's heads harmlessly wide.
Teams out at Old Trafford and two changes for the home team as Michael Carrick and Phil Jones replace Luke Shaw and Ander Herrera. Arsenal are unchanged. We're back under way in this quarter-final.
Half time: Manchester United 1-1 Arsenal
I asked for some entertainment before kick-off and both teams have produced in an engrossing first half. Arsenal led through Nacho Monreal but for just four minutes as Wayne Rooney powered a header beyond Szczesny. Both teams look like adding to their lead at will and the second 45 minutes could be a tasty affair.
Szczesny made a hasty clearance and though the United fans are screaming for a shot from range, the home side build nicely and Fellaini produces a low stop from the Polish international.
A long hopeful ball that doesn't end with Fellaini bringing it down almost ends with a United goal as Valencia chips the ball over Monreal and finds Di Maria, who allows the ball to bounce and forced Szczesny into a good low save at his near post.
Van Gaal's side much improved since their goal, moving the ball faster in attack and they almost find a second when Rooney finds Di Maria who brings it under his spell but has the ball taken off his toes by Koscielny as he goes to pull the trigger.
Yellow card for Angel di Maria for a wild challenge on Alexis Sanchez, who has been a bit quiet in recent minutes when on the ball has caused United some real problem. The results free-kick is right into the arms of De Gea.
Before that Welbeck chance it's arguable that Arsenal should have had a penalty when Marcos Rojo grabbed hold of the England striker, who went sprawling in the United box but had his appeals waved away.
Danny Welbeck almost puts Arsenal back in front as Oxlade-Chamberlain stands up a cross towards the back post and Welbeck heads down but De Gea makes an easy looking save.