This Sunday, Manchester United host Liverpool at Old Trafford while Chelsea meet Arsenal at Stamford Bridge.
It could be the key afternoon in deciding the destination of this season's Premier League trophy.
Will United steal a third successive win over their north-west rivals? Can Arsenal get their faltering title bid back on track? And can Chelsea keep their own championship hopes alive?
Nigel Winterburn, who won the title three times while at Arsenal, takes BBC Sport through the key battles.
"Liverpool have to nullify Cristiano Ronaldo's threat.
As a full-back you make your opponent do what he doesn't like to do. If he likes to go down the wing, you'll cut off the room out wide and force him inside.
Show Ronaldo outside and he's got the pace to beat you; show him inside and he will still cause you problems.
Liverpool must use the full-back and midfielder - probably Javier Mascherano - in tandem. If Ronaldo does get the ball, the midfielder comes across so the space both inside and outside Ronaldo can be closed down. "
"Fernando Torres will be the main threat to United.
His movement is exceptional. He makes clever runs - little bendy darts across the back four, or a diagonal run between the two centre-backs or between centre-back and full-back.
He can either drift behind you or sit in the space between the centre-backs and the midfield. That gives defenders problems.
Do you go with him, and then leave a space in behind that someone like Steven Gerrard can exploit, or do you let him go and risk giving him all the time and space he wants?"
"Arsenal have lost just one league game this season, but they've also drawn too many - notably four out of the last four.
That's where Emmanuel Adebayor comes in. After scoring 12 times in nine games, he's only got one in the last seven.
He actually says he's playing as well as he was before - it's just that those chances that were going in before are now being saved or hitting the woodwork.
It's a very fine line sometimes, and Arsenal need him to get on the right side of it again."
"Chelsea's biggest problem is how they use strikers Didier Drogba and Nicolas Anelka.
There's no reason why they can't play together - Drogba as the target man and Anelka coming short or making runs beyond him.
But Avram Grant doesn't play them like that - he prefers a lone man up front with two wide men coming in either side of him.
Will he change the system? You wouldn't think so. And the way that Drogba's played against Arsenal in the past should mean that he is the one to start."
"Chelsea are usually rock-solid defensively. John Terry is good in the air, Ricardo Carvalho is wonderful on the deck and their midfielders are usually very well organised.
Against Barnsley in the FA Cup and against Spurs in the league in midweek Chelsea looked fragile. They have conceded four goals twice in the league this season and Manchester United have a much better goal difference. Arsenal will look to exploit that uncertainty between defence and midfield and Chelsea's slight dip in confidence."
"These are the sort of games that top-class players relish.
You know that you're playing at the absolute top of your profession, on the biggest stages in domestic football and against its best players. And that's what you want.
Do you get nervous? Yes - but not apprehensive. You have to relish the occasion. When you feel the butterflies, you know you're ready.
The manager does his work in the days leading up to the match. Once the game starts, they're relying on their players to get things right for them."
Nice build up to the Grand Slam Sunday from BBC.
I so cannot wait till we beat Liverpool hehe