United suffered a 2-1 defeat to their Premier League rivals in the FA Cup quarter-final tie at Old Trafford on Monday.
Nacho Monreal put Arsenal in the lead in the 25th minute when he found the target from close range after some great footwork from England international attacker Alex Oxlade-Chamberlain.
Although Wayne Rooney restored parity just minutes later with a header from an Angel di Maria cross, Danny Welbeck’s strike on 61 minutes settled the tie.
United’s performance was once again disappointing, and manager Van Gaal’s decisions were called into question yet again, especially the one with Radamel Falcao.
The Colombia international did not start the FA Cup tie against Arsenal, but many would have expected him to make an appearance as a substitute in the second half.
However, Van Gaal did not bring Falcao on even with United 2-1 down, a decision which has bemused many football followers.
Forest striker Blackstock was following Monday’s game, and he, too, did not get why the 29-year-old former FC Porto and Atletico Madrid star did not feature against Arsenal.
You can't end the game with Smalling upfront and Falcao sub not used— Dexter Blackstock (@dexblackstock23) March 9, 2015
Falcao has struggled with form and fitness issues throughout the campaign, but he should have still been called upon against Arsenal in the second half.
Maybe the fact that United were a man down due to the dismissal of Di Maria dissuaded Van Gaal from throwing out a striker into the mix.