Man Utd 3-2 Arsenal: Why Arsenal fell short, again - Ian Wright
Arsenal's defeat at Manchester United was especially disappointing because it showed they do not have the mental strength to deal with being where they are at in the title race.
Gunners fans know they have a fantastic opportunity to win the Premier League this season, but the team does not seem to understand the enormity of their situation, and what it requires.
There are still 11 games to go but, as things stand, I do not watch them and see a team that has what it takes to win the title.
I don't know who is going to win it out of Leicester and Tottenham, but I do believe it is between those two now.
'The pressure was on'
With Leicester beating Norwich on Saturday, and Tottenham playing Swansea at the same time as Arsenal kicked off at Old Trafford, the circumstances demanded hunger and intensity from Arsene Wenger's side.
The pressure was on the Gunners to get a good result, but I felt they had a great chance to pull it off.
They were close to full strength, while United were fielding a weakened team, including some kids and a makeshift defence.
But instead of raising their game because they knew what was at stake, Arsenal began badly and did not put United's frail back four under any pressure until they were already 2-0 down.
It was not the sort of start that you make to a game that you feel you have to win, and they were punished for it.
United fully deserved their victory - Arsenal came up short, again, and it was a hugely frustrating day.
What went wrong?
Arsenal's main attacking players - the likes of Mesut Ozil, Alexis Sanchez and Theo Walcott - all struggled to get going.
So it was one of those games where the Gunners had to stay solid at the back, but they were poor in that department for Marcus Rashford's first goal.
That got United going - as soon as they scored they seemed to realise 'Arsenal are not up for it today' and you could see their confidence grow.
I thought Juan Mata and Morgan Schneiderlin were brilliant but Rashford is obviously going to get the headlines for scoring two goals and making a third, and rightly so.
His movement off the ball was fantastic, and he finished with such composure too.
How good is he? I think we need to see him in a few more games to find out but this was a massive step-up in class from his debut against FC Midtjylland on Thursday, and he has still delivered the goods.
'Pressure only going to build on Arsenal from here'
Unlike the Gunners, Leicester and Spurs both did what you do when you are in a title fight, which is find a way of winning, even when things do not go your way.
I was in the Match of the Day 2 production office watching both of Sunday's Premier League games and I saw the way Spurs celebrated their victory.
On paper you might think beating Swansea 2-1 at home is no big deal but their fans knew how important it was, especially with their team coming back from 1-0 down.
When you win the title, you look back at the whole season and it is days like this that make the difference. If Spurs do end up as champions, then this was huge win for them because it keeps the pressure on Leicester, and also helps them build the belief they need.
For Arsenal, it is the opposite after this weekend - they are already doing what they always seem to do if they are in contention at this stage, which is fall away, and the pressure on them is only going to build from here.
All season they have had the opportunity to get a consistent run going and put the other teams at the top under pressure.
But they have not been able to do that yet - they have already had one wobble at the start of 2016 where they failed to score in three out of four Premier League games and only picked up three points.
At the moment they simply do not have the drive and determination they need.
Ian Wright was speaking to BBC Sport's Chris Bevan.