Jose Mourinho has questioned Pep Guardiola's honesty over David Silva's injury.
Alex Shaw previews this week's Premier League action and highlights five key storylines in this edition of W2W4.
1. Manchester derby a potential season-definer
What really happens when an unstoppable force meets an immovable object? We'll find out this Sunday when Manchester City, who have won every away match in the league this season, face Manchester United at Old Trafford. Jose Mourinho has overseen a 40-match unbeaten home record so something is going to give.
Mourinho won't need reminding that he has turned Old Trafford into a fortress only after suffering a chastening 2-1 defeat to his great rival Pep Guardiola in September last year. He will, though, presumably relish being the only man left who can prevent Pep and City from equalling a Premier League record of 14 wins in a row. If you needed one man to come and spoil a party, you'd choose Mourinho.
United's 3-1 win at Arsenal last time out, one of the great games in recent years, had everything. But it says a lot about the magnitude of Sunday's fixture that even in the lead up, it feels like it has everything already. Records on the line, two warring rivals head-to-head, some of the league's best players -- though no Paul Pogba, as he's suspended -- and a title race that could either be blown open or drift towards a procession. So much is riding on this fixture. The psychological boost a victory would give cannot be underestimated.
Manchester City, 2-1 winners over Huddersfield, Southampton and West Ham in their last three, have slowed in recent weeks. But Shakhtar Donetsk proved Guardiola's men are not unbeatable. You feel if we are going to get a proper title race, a Mourinho masterclass over his one-time ally is needed and that yawning eight-point gap needs shutting.
Two great rivals go head-to-head as Manchester United look to halt Manchester City's inexorable charge to the title.
2. Everton to end Mersey misery?
It's not difficult to sell a Merseyside derby -- the ferocity on the pitch always mirrors the fanaticism off it -- but Everton need to start holding up their side of bargain.
They've been wretched in this fixture for far too long, not tasting victory at Anfield in 18 years. Everton are also winless on the road in 15 attempts against anyone and last beat Sunday's opponents seven years ago. As omens go, it looks as forlorn as Everton's performances against their neighbours have been.
And yet, there's a glimmer of hope. With Sam Allardyce barking orders from the touchline, could Everton finally upset the Reds? Allardyce was the last manager to come away from Anfield with a victory when his Crystal Palace side defeated Liverpool 2-1 on April 23 and has enjoyed facing them in the past, with three of his six wins against them coming in his days as Bolton boss.
Cast as fire-fighter once again to stem the threat of relegation, Allardyce's arrival was met with a mixed reception at Everton with plenty pondering whether his abrasive style of play fits with the so-called "School of Science." The visiting fans, you'd suspect, would happily take an offensively bad performance on Sunday if it resulted in a first win at Anfield since 1999.
If Everton are going to limp away from trouble, three points on Sunday will give them a shot in the arm and Allardyce will win the hearts of a fanbase that needs some convincing.
3. Sanchez or Ozil?
Had you offered Arsenal fans the chance to keep just one of Alexis Sanchez or Mesut Ozil at the start of the season, the former would have won by a landslide. Now, though, the tables have turned. While Sanchez was underwhelming (a regular theme) against Manchester United in last week's 3-1 defeat, Ozil continued his strong form. Probing and penetrative -- as well as exhibiting a new-found work ethic and appreciation for defensive duties -- Ozil excelled against Mourinho, a man who he could yet play for if the gossip columns are proved right.
So, which one would you pick? Sanchez has been off-key this season and has only scored three times. By contrast, his three against West Ham this time last year took him to 11 goals for the campaign. Arsenal will need the Chilean and Ozil on top form away at Southampton as Arsene Wenger's men look to put last weekend's disappointment behind them.
Tottenham need a win to keep in touch with the top.
4. Tottenham need to click into gear
Tottenham are unbeaten in the Premier League following a Champions League assignment in midweek this season, drawing two and winning three -- including a rousing 4-1 win over Liverpool. However, in the lead up to Champions League matches, they've been poor, including defeats at Manchester United and Arsenal and a draw at Watford.
The identity of the teams they've drawn against immediately after Champions League football, Swansea and West Brom, is sure to make Mauricio Pochettino wary ahead of Stoke's visit to Wembley. Spurs would have had no bother in seeing off Swansea and the Baggies at home last season but this time around, they've had it far tougher.
Tottenham have struggled at the national stadium this season -- wins over Liverpool and in the Champions League against Borussia Dortmund and Real Madrid aside -- and if they're serious about a top four place or pushing to get back into title contention, victory against an also-ran like Stoke is imperative. Mark Hughes' men have won just eight out of their last 32 matches -- almost an entire league season.
5. Hart ache for Moyes
David Moyes said he didn't do enough due diligence when he took the Sunderland job last summer and you wonder if he looked at the fixture list before saying "Yes" to West Ham. An opening trip (and resultant 4-0 hammering) to former club Everton was tricky enough before visiting Manchester City and then facing Chelsea and Arsenal.
It's likely he'll therefore kick off his Hammers reign with four successive defeats. To avoid that, a win at the London Stadium over Antonio Conte's Chelsea would go some way into breathing life into West Ham's season.
Alex Shaw is General Editor at ESPN FC. Follow on Twitter: @AlexShawESPN.