On Saturday the two top sides face off at Stamford Bridge, and the result could go a long way to deciding whether it's Chelsea or Manchester City who are crowned Premier League champions at the end of the season.

Chelsea head into the match with a five-point advantage at the top of the table, but Jose Mourinho is fully aware that the title race is far from over. A Chelsea win could hammer one nail into the City coffin, but a triumph for the visitors will turn up the pressure on the side from West London.

Below, Sports Mole takes a look at a few of the key talking points ahead of the biggest match of the season so far.

1. Can Didier Drogba replace Diego Costa?

Liverpool fans were furious, Mourinho attempted to stay silent and Diego Costa decided to launch an appeal. It's been a hectic few days for Costa, who was charged by the FA for violent conduct after appearing to stamp on Emre Can on Tuesday evening. As we all know, appeals very rarely end in success for the player, and it's safe to assume that Costa will be suspended when City arrive at Stamford Bridge. Chelsea are backing their striker, but the appeal seems to be in desperation.

If Costa does miss out, it will be down to Mourinho to decide who comes in to replace the influential forward, who has scored 17 goals in 19 Premier League games, and the safe bet is to back Didier Drogba to lead the line for the hosts. In his first spell at the club, Drogba was the man Chelsea turned to in the biggest games, and more often than not, he would deliver the goods. He produces his best on the big stage, and the pressure is on him to roll back the years on Saturday. Is Drogba the same player he used to be? Of course not, but he has the experience and intelligence to pose a big threat to a City defence which has the tendency to offer too many opportunities to opposing sides.

Unless Loic Remy comes in as a surprise replacement, Drogba will be the man trusted to lead the Chelsea attack. In what looks certain to be his final season in a Chelsea shirt, can the Ivorian add to his collection of famous goals?

2. Risks on the mind for Manuel Pellegrini

We've heard it all before. The title can't be won in this match, but it could be lost. Manuel Pellegrini knows better than anyone that a loss to Chelsea could kill off City's title bid, but he'll also be aware that a win piles the pressure back on the shoulders of Mourinho's men. It's a difficult gameplan to work out, but a brave approach from the Chilean could be the best way to go.

Sergio Aguero has had his injury problems this season, but the Argentine is a certainty to start at Stamford Bridge. It's deciding who supports him when the difficulties crop up for Pellegrini, who must choose whether to pack the midfield or use either Eden Dzeko or Stevan Jovetic as a partner for Aguero. Even when Roberto Mancini was in charge of the Citizens, he would often prefer to use Dzeko and Aguero as a partnership in an attempt to occupy the opposing side's central defenders. Yaya Toure remains at the Africa Cup of Nations with Ivory Coast, which means that Fernandinho and Fernando are likely to start in the centre of midfield. Neither player is strongest going forward, but their selection could allow Pellegrini to take more risks further up the pitch.

Samir Nasri is out with injury and Jesus Navas has struggled to produce his best form this season, and those two factors should persuade Pellegrini to use James Milner and key man David Silva behind a front two. Milner is one of the few City players who can thrive at both ends of the pitch, and he rarely lets his manager down in big games. If Pellegrini wants to leave the capital with three points, playing to his side's strengths will be vital. A draw would be a decent result, but it would be a good outcome for Chelsea, too. The pressure is on the City boss to weigh up the risks and rewards.

3. Silva vs. Matic

Is there a more important individual battle? City's most creative player coming up against Chelsea's seemingly impenetrable force in midfield. Very few frustrate opposing players like Nemanja Matic, whose performance levels never seem to drop below outstanding, but Silva is surely on of the most difficult midfielders to keep quiet.

In truth, it may not be the moments when the pair are close together which will make the difference, but rather what impact their respective reputations can have on the other. Silva always starts matches wide, but the Spaniard has free licence to roam in this City team, and the champions are at their best when the playmaker is getting as many touches as possible in and around the box. Unfortunately for Silva, that is Matic's territory. However, the presence of Matic could force Silva to look for space elsewhere and the early battles between the players could decide which approach Silva adopts.

On the other side of the coin, Matic's eagerness to keep Silva quiet could have a detrimental effect on his own side's performance. If Mourinho asks the Serbian to follow Silva as closely as possible, it will be down to City's other attacking players to capitalise on the space created by their teammate. The chances are that both players will produce yet another excellent display, whether they're on the losing side or not. Silva's magic in the final third vs. Matic's intelligence in defensive areas. It's a mouth-watering battle which could decide who collects the points.

4. The Frank Lampard factor

Frank Lampard is a Chelsea legend. There's no debating that fact. The midfielder is the club's record goalscorer, he played a key role in starting their most successful period ever, and some would argue he might be Chelsea's greatest ever player. However, the Lampard tale could take another big twist on Saturday.

In September the former England midfielder scored the equaliser in a 1-1 draw between these two sides. There was no celebration and almost an apologetic look on the face of the former Blues star. It was difficult to accept for Chelsea fans, but they expected to only come up against him once. Months of speculation and gossip followed, and it's finally been confirmed that Lampard will be with City until the end of the season. Can he come back to haunt Chelsea again? Will the Stamford Bridge faithful ever forgive him if he swings the title race back into City's favour? Of course, we can only deal in hypothetical situations before the game, but even at the age of 36 it wouldn't be a surprise to see him make an impact at some stage.

Chelsea were given plenty of glorious memories by Lampard, but if they're forced to watch him lift the title with City in May, it's that image which could be most difficult to forget. All eyes will certainly be on him at Stamford Bridge.