Manchester United delivered one body blow to an English Premier League title rival at home last weekend and they will be out to do the same on enemy territory when they visit Chelsea tomorrow night.
These two clubs have shared the championship between them for the past six seasons and, even if this season's evidence makes it unlikely that we will have the usual two-horse race, this is always a highly significant encounter.
Chelsea have held the upper hand in the games at Stamford Bridge, where United have not won in eight visits in the league and cup since Roman Abramovich became owner of the west London club (five wins for Chelsea and three draws).
That record is in line with Chelsea's overall figures at home to other top-four finishers in the Abramovich era, with 13 wins out of 21 (62 per cent) before this season and just two defeats. This season they have embellished that record with a 2-0 home win over Arsenal, but that was before the slump that has seen them fall from a clear lead at the top of the table to fourth place.
Chelsea have won just three of their 10 Premier League games since that success over Arsenal in early October and those victories came against Blackburn (currently 13th in the table), Fulham (17th) and Wolves (19th). That is uninspiring form going into a crunch match against undefeated United, but there are some positives for Chelsea.
One is that their home form remains strong, apart from the calamitous 3-0 defeat by Sunderland five weeks ago. They have conceded only one goal in their other seven home games and the recent return of John Terry suggests their defence will not crack so easily again.
Frank Lampard's probable return to the starting line-up in midfield is another huge boost for Chelsea, who missed his energy and goal threat during his 15-week absence before coming on as a late substitute in last week's 1-1 draw at Tottenham.
Chelsea have won 15 of the 20 Premier League games Lampard has started in 2010, with the midfield dynamo scoring in half of those matches. It is probably no coincidence that their goal tallies have gone down during Lampard's absence and his return, if fully fit, will make Chelsea a far better side.
For all the foreign talent that has poured into the Premier League, the best teams have had a strong English heart and Chelsea are no exception, with the passion of Lampard and Terry a key ingredient in their success.
Chelsea's problems have been the focus of media attention in recent weeks, but United are not without their faults, despite the good impression created by their unbeaten record and their move to the top of the table with last week's home win over Arsenal.
Wayne Rooney is still not at his best and the rest of the attack blows hot and cold, which helps explain why they have drawn six and won just one of their seven away games. On the road they have scored 11 goals, at an average of 1.57 per game, whereas at home they are averaging 2.78 goals per game.
United have drawn all three visits to current top-half teams, two of them without scoring, and may not have enough firepower to grab their first win at Stamford Bridge since April 2002. Chelsea could be on the verge of a return to full strength, but that has to be taken on trust on their recent form and a draw, probably low-scoring, looks the best bet.
The best away chance on the Premier League programme is Tottenham, who visit Blackpool, although the odds are plenty short enough. Blackpool's home form does not match their away record, but they could be open to improvement at Bloomfield Road and the odds seem to dismiss them too easily considering they are only five points behind Tottenham approaching the halfway point of the season.
That leaves five home teams to consider - Arsenal, Liverpool, Blackburn, Wigan and West Brom. The first two are obvious, but the others appear to offer some value.
Blackburn are in a state of flux following the departure of Sam Allardyce - a change of management that, like Chris Hughton's removal at Newcastle, appears to make little sense - but they are the clear form choice based on their excellent home record against bottom-half teams and West Ham's poor away form.
This season Blackburn have won four and drawn one of their five home matches against current bottom-half teams, having gone undefeated last season in that category (seven wins, three draws). Overall, Blackburn have conceded just nine goals in 15 home games against bottom-half teams since the start of last season, with a 73 per cent win rate.
West Ham are the lowest away scorers in the Premier League, with only four goals in eight games, and realistically they have to hope that Blackburn are unsettled by Allardyce's departure.
Wolves are poor travellers, too, with just one point out of a possible 24, and even the short trip to bitter rivals West Brom might be too much for them. Three of the four home matches in which West Brom have dropped points were against top-six sides and their form is good.
Wigan are a more speculative pick, but this could be a good time to play Aston Villa, who have been brittle on the road. Wigan could reward backers on the handicap at least.
Shortlist: Dortmund, Blackburn, Derby, QPR, Portsmouth, Swansea, Colchester, Charlton, Southampton, Carlisle, Ipswich, Mainz, Milan, Real Sociedad.
Top five bets
1 Dortmund away win
100 per cent on the road and going from strength to strength
2 QPR on handicap
Remain a tough side and can bounce back from last week's first defeat
3 Ipswich home win
Risky, but at big odds are worth chancing to emerge from their slump
4 Milan home win
In great form and opponents Roma yet to win outside the capital
5 Real Sociedad home win
Overpriced with Valencia having won only two out of seven against top-half teams