How he fared against more experienced opponents with just a few Premier League appearances to his name?
How nervous he must have felt despite all that in-built bravado that took him all the way to one kick away from deciding a Champions League final?
Now there is another youngster attempting the same journey, playing in the same position.
Andreas Christensen hails from Lillerød in Denmark rather than Barking and may not appreciate any comparison with the Chelsea’s former leader, who just happened to be turning out at Preston for Aston Villa last night. But on the same path he most surely is.
And already he has discovered how tough it is going to be. It was his error that gifted Lionel Messi his long-awaited first goal against Chelsea.
The 21-year-old supplanted Gary Cahill for the visit of Lionel Messi and Luis Suarez in a team where the manager has already decided he can do with David Luiz, who was once the globe’s most costly defender.
And like Terry and so few between he has come through the ranks at a club notorious for failing to promote young talent since Terry established himself as the ‘captain-leader-legend’ of the fans’ banners.
But was Christensen nervous? You bet he was – and it showed.
An early interception was clumsy but nothing on an attempted pass across his own box that went out for a corner. Yet nothing came of that and the young Dane grew into the game steadily.
Last season he had been allowed a dress rehearsal, of sorts. Chelsea youngsters inevitably get loaned out, often to oblivion, but a two-season spell at Borussia Monchengladbach was a big indication that he was being earmarked for profitable use.
Twice he played against Barcelona in the Champions League last season, a 2-1 loss at home and then a 4-0 mauling at the Nou Camp. That represented a steep learning curve but, again, how many Chelsea fans are aware of any grave errors committed in those games?
This was the test that mattered against opponents Chelsea somehow managed to get past in the 2012 semi-final when Terry managed to get himself sent off before half-time.
Christensen was in the right place to stop a foray forward by Suarez and did the same to repel Messi not long after, although nerves again got the better of him and possession was quickly surrendered.
The half time whistle – and zero Barcelona goals – was proof of a job half done but well done by a player Frank Lampard had praised for being good enough to keep Vigil van Dijk out of the side had the Southampton man not chosen Liverpool over the champions last month.
Indeed, speculation had been swirling around before that £75million deal was concluded that the Dane was on Barcelona own transfer radar.
The second half began with a foot to halt Messi and a muscular shepherding of Suarez away from goal, although the Uruguayan’s trickery required Victor Moses’ arrival to complete the task.
The hour mark came and went without a Barcelona goal and Willian’s fine strike at the other end quickly followed.
Then came the moment he will be desperate to forget, the reckless ball across his own box meant for Cesc Fabregas but succeeding only in allowing Andres Iniesta to set up Messi for a needless equaliser.
If JC is to become the new JT then he will have to recover from setbacks like this.