Arsenal's woeful performance in the League Cup final stole most of the headlines this weekend, partially obscuring the fact we had a fascinating round of Premier League fixtures. Defeats for Everton, West Brom, and Chelsea felt hugely significant, and with ten games remaining we now have a clearer idea of which clubs will be fighting for the lives right through until May.
A surprising new formation for Jose Mourinho gave fresh hope to United fans, Liverpool's full-backs hinted at a bright future without Philippe Coutinho, and Tottenham's late winner hid some tactical deficiencies that need addressing.
Here are three things we learnt from the weekend action:
1) Mourinho's surprise front three gives United the attacking edge
The biggest shock of the weekend was Jose Mourinho's formation and line-up for the visit of Chelsea. Rather than mimic the visitors' formation, he played with four at the back and Alexis Sanchez in the hole behind strikers Romelu Lukaku and Anthony Martial, creating a very attacking line-up - and a first for Mourinho as Manchester United manager.
As a result Chelsea had more chances than we would have expected in what was quite an open game. Eden Hazard and Willian both excelled as inside forwards because of the lack of bodies in central areas; United had a flat back four and three midfielders in front, meaning there was plenty of space around them – and even more so on the flanks, where Victor Moses repeatedly isolated Ashley Young.
However, the gamble ultimately paid off for United, whose system specifically targeted Chelsea's use of a two-man central midfield. Both United goals involved Lukaku, Martial, and Sanchez playing in a triangle shape in the middle, maximising the space around N'Golo Kante and Danny Drinkwater. It was a tactical master-class from Mourinho, who deserves significantly more praise than he was given by the media on Sunday.
2) Robertson and Alexander-Arnold offer Liverpool a fresh approach to breaking down defensive opponents
Pundits agree that Philippe Coutinho's move to Barcelona is only going to hurt Liverpool when they're facing very defensive opponents, because it is in these games that the Brazilian would drop deep and thread passes through the crowd. However, Liverpool appear to have adapted their tactics to find another route to goal against low blocks: the crosses of Andrew Robertson and Trent Alexander-Arnold.
Both are exceptional crossers of the ball, and it was their constant early peppering of the West Ham box that earned the corner for the Liverpool opener. Once a goal down, the visitors were forced to come out of their shell and play the ball more in the centre, which allowed Liverpool's gegenpress to pick them off and get runners in behind.
It is easy to launch crosses into the box against deep-lying teams, who rarely step up enough to block such attempts by full-backs. However, few teams possess such brilliant technicians in this regard; Liverpool now have a new template to break down stubborn defences and force their opponents to move higher up the pitch.
3) Tottenham's poor in-game tactical choices is costing them points against bottom-half clubs
Spurs entered this match having failed to win each of their last two games against clubs in the bottom half of the Premier League – and it was almost three in a row before Harry Kane's late winner at Selhurst Park. They did just enough, and many will argue late winners in tough matches shows the hallmark of champions, but Spurs fans should be worried by the lack of tactical awareness shown by the players on Sunday.
Firstly, Spurs failed to control the Crystal Palace counters, with Andros Townsend getting behind Ben Davies on four separate occasions in the first half. The Welshman should have read this situation considerably better. But more importantly, Spurs attacked consistently down the left via Davies despite the fact that Alexander Sorloth wasn't tracking back on the other flank, leaving Patrick van Aanholt exposed.
Mauricio Pochettino – and his players – should have noticed where the space was, rather than repeat their usual attacking build-up play over and over. Victor Wanyama was entirely unnecessary in central midfield (he failed to make a single tackle or interception) and should have been taken off much earlier – with Lucas Moura his replacement. The Brazilian, who only got 24 minutes, was the perfect player to take advantage of Palace's under-stocked left flank.
In future games, Spurs won't grab that late goal – and it will be their own fault for too rigidly sticking to their pre-match tactical instructions.
Best of the Week – Jose Izquierdo
Brighton's left-winger Jose Izquierdo has gradually become accustomed to the speed of Premier League football over the last two months, amassing two goals and three assists in his last five starts. Against Swansea City, his pace and width handed Brighton the initiative against a Swans team we know to be weak in the full-back positions.
Linking superbly with Pascal Grob, Izquierdo increasingly looks like the man who will keep Brighton in the top flight. His energy is the perfect weapon on the counter-attack and, striking fear into defenders, significantly helps Chris Hughton's side take the territorial initiative in relegation six-pointers.
Worst of the Week - West Brom's defending
Alan Pardew looked like a broken man when Huddersfield Town took a two-goal lead in the 56th minute at the Hawthorns on Saturday. As fans streamed out of the ground, his players appeared to lose all confidence, a sure sign that faith in the manager has been lost. It seems almost impossible that Pardew will remain at the club beyond next week.
Curiously the issues are not at centre-back. Ahmed Hegazi and Jonny Evans are very good defenders but they don't receive enough help from midfield, which is to say Pardew's use of a 4-4-2 is baffling. They are light in the middle, forcing them into cautious decisions when hoping to counter-attack and allowing more aggressive midfields, such as Huddersfield's, to dominate.