An interesting feature of Jose Mourinho's return to Chelsea has been his fondness of Branislav Ivanovic. The Serbian signed in the months following the manager's original departure in 2007 and although he didn't make his debut until eight months after he signed, he has since emerged into one of Chelsea's key players in the years that followed, first as a right-back - and impressively so under Carlo Ancelotti - but also proving a useful utility when switching into the centre.
It's quite remarkable to think back over the trajectory Ivanovic's career has taken since coming to Chelsea. There was that famous headed brace against Liverpool, the decisive goal in the Champions League tie against Napoli, last season's winner in the Europa League final as well as some outstanding defensive performances, including the Barcelona tie in 2012 where Ivanovic struck up an unorthodox centre-back partnership with Jose Bosingwa, yet a 10-man Chelsea still progressed to the final (which Ivanovic missed due to suspension).
Many expected him and Cesar Azpilicueta to rotate under the new tenure - but rather contrastingly, Ivanovic has played every minute (810) in the Premier League, with Azpilicueta's time (29 minutes) limited to a few substitute appearances. Granted, the Spaniard started in both Capital One Cup ties and in the Champions League against Schalke, but it is clear Ivanovic is firmly Mourinho's first choice in a position where many thought the competition was, at least, evenly balanced.
Granted, Azpilicueta's involvement at the Confederations Cup didn't help, but more significantly, the commentary for the Arsenal match mentioned Mourinho's specific praise of Azpilicueta's work ethic in the matchday programme. That backed the general feeling that this isn't so much an issue of meritocracy, but instead grounded in tactical issues.
There are, in essence, three reasons. Firstly is the fact that Ivanovic is, rather obviously, a decent full-back. There are flaws to his game, yes, but he makes powerful forward runs and back when Chelsea had a more physical number nine (Didier Drogba) he developed an unusual penchant for hitting accurate crosses with the inside of his right foot.
But while Azpilicueta might be technically better but Ivanovic is clearly far more physically gifted. That is reflected in the tally of headed goals that he scores (and the flick-on for Torres' first goal against Schalke is a relevant, recent example), as well as the contribution he makes towards defending set-pieces. Mourinho has always been keen to pack height into the side, especially in the Premier League - in great contrast to Rafa Benitez - and Ivanovic in that sense is ideal.
The aerial ability leads into the second reason. There's no need to quantify the fact Chelsea's crop of attackers are in essence a pack of midgets, which...isn't ideal for trying to win long balls. Granted Mourinho has not got Chelsea playing like Stoke and the majority of play stems from distribution through the defence but there will always be times when this is not an option.
In those instances we have seen Ivanovic move unusually high up the right side and Cech aim his goal-kicks towards him. It's a clever workaround to a small detail that might seem unnecessary but it was the passage of play that lead to Fernando Torres leaving Gael Clichy in his wake as he set up Andre Schurrle for the first goal against Manchester City.
Thirdly, as Graham has touched on before, Ivanovic is key to Mourinho's most frequent formation change this season - the three at the back Hail Mary when chasing games against weaker opposition. I'll quote him here:
Branislav Ivanovic is the man who allows this all to happen. His ability to play both centre back and right back (and it's not unreasonable to suggest that his ideal position might be as something in between) means that Chelsea can switch from a four-man back line to a three by withdrawing the left back from an attacking player, which is what Mourinho's done each time he's moved to 3-5-2.
As Graham explains further in that article, you can't really do this with the smaller, less physical Azpilicueta. The Spaniard might have scored his first Chelsea goal against Arsenal, but it's still highly unlikely he'll feature in the upcoming match against Newcastle, for the three reasons listed above. Newcastle are one of the more direct sides in the league and Ivanovic's heading should certainly prove useful. Furthermore, Newcastle will be one of the sides Mourinho expects to beat, so he'll certainly want to have the mid-game option of switching to the three-man defence up his sleeve in the event things don't pan out the way he expects.
There's certainly a debate to be had about who is the better right-back, but for the system Mourinho uses at Chelsea Ivanovic is, for now, clearly first-choice.