What we've learnt from the opening Premier League weekend

We also learnt Lee Cattermole can shoot

Manchester United fans learnt that a new manager doesn't cure all ills and Chelsea fans learnt that Diego Costa's bad World Cup means nothing. Alex Johnson rounds up what else we learnt from the opening weekend of the Premier League weekend.

The first weekend of the Premier League signaled the start of nine months of action-packed and unpredictable football.

It might be early days, but what did fans and pundits learn from the opening round of fixtures.

Last season's Chelsea were not really a typical Jose Mourinho side. He knew where they lacked - mainly goals - and planned for a summer of spending to make them genuine title contenders. He moved quickly to secure his big two signings and they look like master-strokes after just one game. Diego Costa brings goals to Chelsea and his power will trouble Premier League defenders. Against Burnley he got his first and looked a handful - he also should've had a penalty.

Cesc Fabregas also looked a fantastic addition. His Premier League experience is key and he has the skill to unlock teams that park that bus - something Chelsea struggled to do last season. The side Chelsea put out against Burnley looked a proper Mourinho side. They are really balanced in midfield as Nemanja Matic holds and Fabregas creates. Ahead of that Oscar, Eden Hazard and Andre Schurrle are full of tricks and create openings. And then Costa is there to upset defenders and get goals. It is a tantalising attacking prospect and they can even call on Didier Drogba - it's going to rain goals for Chelsea.

It was glaringly obvious on Saturday that Manchester United need to sign top players quickly. The shock defeat to Swansea at Old Trafford showed that very little appears to have changed at the club. There is a new manager in Louis van Gaal and there was a new optimism, but that quickly drained away as Swansea got a well-deserved win.

United were poor and the game showed there are big holes in that team. Van Gaal switched formations and tried a couple of youngsters, but things didn't click. Ander Herrera was the only new face and it proves the chequebook needs to be opened. In defence they were poor and the midfield lacked creativity. Before the transfer window closes, van Gaal has a lot of work to do. United need possibly four world-class signings if they are to think about getting back into the Premier League top four.

The first weekend showed how unpredictable the Premier League can be. Very few will have expected to see Swansea win at Old Trafford, or Southampton and Crystal Palace to push Liverpool and Arsenal right to the wire. Of the Saturday games only one of the seven games saw home wins, and that was thanks to Arsenal's late win over managerless Palace. Aston Villa winning at Stoke was unexpected as many pundits expect Villa to struggle and they hadn't won on their travels since New Year's Day. Roy Keane's presence at Villa should make them a tougher proposition, something Villa fans will welcome after two years in the doldrums.

One thing was heard at every Premier League ground - and that was a huge cheer the first time the referee used the vanishing spray. Everyone liked it at the World Cup, and Premier League fans have seemingly taken to it. The novelty will undoubtedly wear off but it was great to hear a huge cheer every time a foamy white line was drawn by the referee. Possibly the one person not happy to see the vanishing spray was Santi Cazorla, who ended up getting spray in his face after referee Jon Moss had trouble with the new technology.