Exhaustion and rotation Wednesday night's game at Craven Cottage was Chelsea's 60th of a draining season. They will probably play twice a week every week until the league ends on 19 May, a workload unmatched by anyone else in England. But Rafael Benitez is a master at managing rotation so that his players are always at 100 per cent.
Attacking quality Chelsea have the best set of creative players in the division, and in the midfielder Juan Mata a player who is a strong candidate for Footballer of the Year, with 30 assists and 18 goals this season. Alongside Eden Hazard, himself finding excellent form, Benitez's 4-2-3-1 system provides the perfect platform.
Tough run-in With Liverpool and Manchester United away and Spurs and Everton at home, Chelsea's run-in is the hardest, meaning they will still have to be at their very best to qualify for the Champions League.
Remaining league fixtures Sunday Liverpool (a); 28 Apr Swansea (h); 5 May Man United (a); 8 May Tottenham (h); 11 May A Villa (a); 19 May Everton (h)
Momentum Arsenal are not playing excellently but they are grinding out results, winning eight and losing just one of their last 11 in the league. In the recent wins against Swansea, West Bromwich and Norwich, the team showed the character Arsène Wenger always talks about. The last few years might have robbed Arsenal of their spark but this is a team that keeps going.
Lack of midfield balance While Arsenal have central midfield options that Spurs or Everton could only dream of, Wenger has not quite found the right combination yet. Santi Cazorla has been moved wide to accommodate Jack Wilshere in the hole, but their most decisive player, Tomas Rosicky, needs to be fitted in too. The result is that Arsenal, slightly muddled in the middle, can take a while to break teams down.
Winnable games Only Manchester United should trouble Arsenal – their other games are against sides for whom they should have too much quality.
Remaining fixtures Saturday Fulham (a); 28 Apr Manchester United (h); 4 May QPR (a); 14 May Wigan (h); 19 May Newcastle United (a)
Running out of legs Andre Villas-Boas was always stretching his squad by taking the Europa League seriously, and midfield pair Mousa Dembélé and Scott Parker have looked exhausted for a while. Spurs have been rather out-run in their last three games, 2-2 draws against Basel twice and then Everton. They will need to find a new level from somewhere.
Gareth Bale Spurs' position owes much to Bale's run of 10 goals in eight matches in January, February and March, during which time he was routinely deciding games by himself. But he went over on his ankle two weeks ago and Spurs have suddenly lost much of their pace, power, imagination and skill. They need Bale back at his best very soon.
Chelsea and City to come Tottenham still have two of the league's form teams to play in Manchester City and Chelsea and they need enough points to keep them in the race.
Remaining fixtures Sunday Manchester City (h); 27 Apr Wigan (a); 4 May Southampton (h); 8 May Chelsea (a); 12 May Stoke (a); 19 May Sunderland (h)
Well-balanced side David Moyes currently enjoys the best range of attacking options he has ever had at Everton – the strength of Victor Anichebe, the skill of Steven Pienaar, the force of Marouane Fellaini and the brilliance of Kevin Mirallas. On top of the usual discipline and work-rate, Everton boast a broad set of complementary styles.
Don't win enough games Everton have only won 14 league games this season, three fewer than Arsenal and Spurs, four fewer than Chelsea, six behind Manchester City and 12 behind United. Realistically they need to win their last five to finish fourth and, based on the season so far, they are unlikely to do so.
Nerve Everton are always competitive but they do not always bend the biggest games – in the league and in the cups – to their will like the top teams, raising questions over their run-in resilience.
Remaining fixtures Saturday Sunderland (a); 27 Apr Fulham (h); 5 May Liverpool (a); 12 May West Ham United (h); 19 May Chelsea (a).
Top of the table
Man Utd 33/26/3/4/75/35/81
Man City 32/20/8/4/58/27/68