Tottenham Hotspur's 3-1 victory over Chelsea at Stamford Bridge has effectively ended the race for the top four and Manchester City's routine win at Everton leaves them one win away from sealing the title; there is very little left to play for at the top end of the table.

But the relegation battle is tighter than ever after West Ham's 3-0 win against Southampton on a weekend in which only two of the bottom nine didn't lose.

Here are three things we learnt from the weekend action:

1) Arsenal can play Aubameyang and Lacazette in the same team

Many onlookers were surprised when Arsenal shelled out £56 million for Pierre-Emerick Aubameyang so soon after spending £52 million on a very similar striker in Alexandre Lacazette, but against Stoke City on Sunday we finally saw evidence of how these two could function together under Arsene Wenger.

Stoke were tenacious and bold in their tactical approach at the Emirates, pressurising the back four into making mistakes and nullifying an attacking threat for long periods; Arsenal only had one shot on target in the entire first half. But that all changed after Lacazette was brought on to play alongside Aubameyang, offering the likes of Mesut Ozil two runners in behind that successfully stretched Stoke to breaking point.

The statistical changes are testament to the difference Lacazette made. Aubameyang had almost as many touches (17) in the final thirty minutes has he did in the first hour (19) while Arsenal managed nine shots on targets in the final third of the match compared to just two during the opening 60 minutes. Stoke were suddenly caught out by that extra runner, which helped Arsenal split open the defence over and over.

2) The performances of Alexander-Arnold & Robertson suggest they might be better off as wing-backs

Liverpool were very flat throughout the match at Crystal Palace on Saturday but eventually made the breakthrough after Jurgen Klopp took the surprise move of shifting to a back three with 15 minutes remaining. The performances of his two full-backs, who became wing-backs for that brief period, suggests we could see more of them in this role over the coming weeks.

In the first half Trent Alexander-Arnold was caught out of position twice by Wilfried Zaha (the second time leading to the opening goal), mimicking his difficulties against Manchester United when Marcus Rashford played down the left.

But in the final 20 he was relieved of defensive duties and looked far more confident higher up the pitch. More importantly, Andrew Robertson was also more threatening towards the end of the game. The Scotland international set up the winning goal from a very advanced position on the left side of the penalty area; Robertson would not have been so advanced had he still been playing as a left-back.

3) Pochettino's half-time switch shows Eriksen is best in the middle

Tottenham Hotspur were very fortunate to go into half-time at 1-1 following a laboured and disjointed first 45 at Stamford Bridge in which the compressed lines of the Chelsea formation restricted space for their more creative players.

For the second half Mauricio Pochettino moved Dele Alli to the left and Christian Eriksen into central attacking midfield, subtly changing the game completely. Not only was Alli more effective now that he could make arcing runs from left to centre on the shoulder of the last defender (such as for his first goal) but Eriksen suddenly made use of the room that opens up around Cesc Fabregas.

The Denmark international was instrumental, playing a superb no-look pass from attacking midfield to put Heung-Min Son in on goal ahead of Spurs' third goal. The lesson here is simple: always play Eriksen in the number ten role.

Best of the Week – Diame & Shelvey

Newcastle United are almost certainly safe after their 1-0 win against Huddersfield Town in which, yet again, the partnership of Jonjo Shelvey and Mohamed Diame ran the game. They took 169 touches of the ball between them and created six chances, while individually Shelvey played eight accurate long balls and Diame completed three tackles and three interceptions.

Huddersfield Town were gradually worn into the ground by these two, who have come to define the tactical patience and efficiency of Rafa Benitez's side.

Worst of the Week – Southampton's 4-4-2

Considering Southampton have a new manager it was very surprising to see them roll over at the London Stadium in what was their biggest match of the season. Mark Hughes bizarrely played a 4-4-2 formation, which meant they were far too light in central midfield and found it very hard to play the ball into the strikers.

West Ham easily defended against their three flat lines, although in truth this match was more about desire and commitment. Southampton just didn't look interested.