Debrief: Man United playing in their own shadow, Arsenal still have their big tests to come

Top Gunners' biggest challenges are yet to come

In Saturday's win over Fulham, Arsenal did what they've done so well so many times this season - remain patient and composed, before killing off their opponents in the second half.

Consistently winning those games that look to be slipping away is certainly no bad thing, but having to battle so long and hard could take a mental and physical toll when the key stage of the Gunners' season hits.

Over the course of 28 days in March and early April, Arsenal will face Bayern Munich (a), Tottenham (a), Chelsea (a), Manchester City (h) and Everton (a). That daunting run could also be topped and tailed by FA Cup quarter and semi-finals, should the Gunners progress that far - not to mention the possibility of a two-legged Champions League quarter-final, should they overcome Bayern.

In previous seasons when the title has been at stake, Arsenal have stuttered as spring has sprung, and the Gunners can ill afford a similar slump this time round. Straining every last sinew to beat Fulham, and before that Cardiff, may appear gutsy, but may leave the Gunners with a little less in the tank during that unenviable month of doom.

Arsenal are in great nick, but their key battles still lie ahead.

Defensive uncertainty costing Liverpool

It was only a couple of weeks ago that Liverpool were on top of the Premier League - now they're suddenly looking over their shoulder with their top-four spot at risk.

The Reds have kept just six Premier League clean sheets this season - the same number as Hull and Crystal Palace, and fewer than West Ham or Norwich.

Luis Suarez and his goalscoring chums have more often than not made that stat all but an irrelevance by rattling in 53 times in 22 league matches, but what happens if the attacking players have a bad day at the office?

Brendan Rodgers' side may have scored twice in their 2-2 draw with Aston Villa, but the attacking verve that has been a key feature of so many of their matches this season largely seemed to have deserted them. The moments of brilliant flair and guile were few and far between - Jordan Henderson's sensational flick to Daniel Sturridge immediately before the striker's goal was one. It's on days like this that a title-challenging team needs a solid defence to fall back on.

Liverpool's back-line - who struggled to cope with Stoke in last Sunday's 5-3 victory in the Potteries - were again pulled from pillar to post, this time by the pace and power of Gabriel Agbonlahor and Christian Benteke.

A lack of communication between the defence and goalkeeper Simon Mignolet was exposed when Benteke was afforded the opportunity to head into an open net after a mix-up between the keeper and Glen Johnson. Matters aren't helped by the tug-happy Martin Skrtel looking like giving away a penalty from every set-piece.

The Anfield side have made many friends this season, but unless they can iron out the creases in their defensive game, it could yet all go to waste.

Sherwood showing something AVB didn't

When Tim Sherwood first took the helm at Tottenham, the football world was agog with talk of the former England midfielder's exotic '4-4-2' formation, a world away from Andre Villas-Boas' 4-2-3-1 (but not that much, when you think about it).

Although the system brought great success in the league, Sherwood's critics were quick to point out that it had left Tottenham exposed and overrun in central midfield during the FA Cup defeat at Arsenal.

It therefore seemed noteworthy that Sherwood opted for a system which appeared startlingly similar to his predecessor's for Sunday's trip to Swansea - and more noteworthy still that it brought with it arguably Tottenham's most consistent and coherent attacking performance of the season to date.

With the reinvigorated Emmanuel Adebayor acting as the focal point, Nacer Chadli and Aaron Lennon bringing width and pace, and the ever-improving Christian Eriksen constantly searching for pockets of space in which to cause mischief, Spurs gave their hosts plenty to worry about right across the pitch.

One of the biggest criticisms of Villas-Boas was that the Portuguese was sticking too rigidly to one system, which was causing his team to be easier to figure out and contain.

Could it be that Borehamwood-born Sherwood is actually more tactically flexible than his exotic predecessor? That would certainly be good news for Spurs.

United lacking all their old qualities

In the past, Manchester United will have played worse than they did in Sunday's defeat at Chelsea, and still picked up at least a point. The difference this season is that they appear to lack the same conviction and bloody-mindedness required to scrape results against the odds.

United had plenty of possession against Chelsea, but had relatively little authority over the match and rarely had Chelsea concerned. There was little of the direct, aggressive play we've come to associate with the Red Devils - indeed, the only aggression came in the form of a couple of misguided lunges towards the end of the match (one of which earned Nemanja Vidic a red card).

David Moyes suggested after the match that the only difference between the two teams was that Chelsea scored from two set-pieces. He's not too far wrong, but the reality is that Chelsea - and hat-trick hero Samuel Eto'o in particular - were far more clinical in a match of few good chances.

Of course, they were without Wayne Rooney and Robin van Persie for the defeat at Stamford Bridge, but traditionally under Sir Alex Ferguson (yes, it's time for THAT comparison again), players like Ji-Sung Park and Darren Fletcher would shine in the big matches - it wasn't always left for the star men to drag the others over the line.

Clearly, what we're now realising in hindsight is the extent to which the pair were doing exactly that last season. The fact is that United's squad is mentally and technically not as strong as it has been in recent years - that's certainly not entirely Moyes' fault - but he simply has to find a way of rebuilding this squad. It'll take more than one or two additions to get this lot challenging at the very top again.

The fact there seemed to be so much satisfaction with the performance is perhaps a sign of how far they've fallen.