There was an interesting moment in the second half of Chelsea's rearguard victory at Anfield on Sunday. Daniel Sturridge had just come on as a substitute with the game entering its final quarter. As Sturridge went to take the ball for the first time, back to the goal, Ashley Cole sprinted forwards and challenged him so hard from behind the impact could be heard in the stand.

Sturridge turned to remonstrate, but Cole had run off to cover some hairline crack in Chelsea's defensive blockade. Seconds later the ball headed for Sturridge again. This time he dithered while Cole nipped in and hoofed the ball out of play before offering some opinions of his own on the state of the game as he ran past Liverpool's centre-forward. Sturridge is not fully fit and found himself tossed late into a game that was already well set. But he did not contribute much after that.

It was a fascinating, pre-planned mini-duel between two players who know each other well and, above all, further evidence of Cole's enduring defensive robustness. There have been plenty of plaudits already for Chelsea's achievement in shutting out the free-scoring leaders of La Liga and the Premier League in successive matches. But for Cole there is a little more to this. Almost unnoticed he is in the middle of an elongated defensive golden run: to date, in 702 minutes of football going back to last year Chelsea have not conceded a goal with Cole on the pitch. Add to this another immaculate half for England against Denmark last month and across 10 matches – seven of which he has gone the full 90 minutes – no team with Cole on the pitch has conceded a goal this calendar year.

It is hard to know exactly what to make of this, albeit the big data approach to football analysis would suggest a clear and actionable trend: if Chelsea want to keep a clean sheet against Atlético Madrid and therefore most likely progress to the final of the Champions League, they need only pick their bearded enforcer and all-round lucky charm and the job is pretty much done. More seriously, there is at the very least evidence here that a player who has been pushed to the fringes at Chelsea and who seemed to be ticking off the weeks until his contract runs out may not be done just yet.

Cole's ability to play to a high level week after week may have dipped with age in the last year, and he may now find himself behind César Azpilicueta, who has developed into a superbly controlled and mobile full-back in his own right. But in the last week he has twice looked superbly assured over the full 90 minutes.

Against Atlético, Cole was essentially a defensive buffer, hardly registering in the outline stats of a game where he made three tackles and 18 passes, but in which he seemed throughout to be gliding reassuringly across Chelsea's left flank, always covering, always in the right space to funnel an attack down a blind alley. Similarly against Liverpool, Cole made just 13 passes, but he was still relentlessly present from his early shot that was well saved by Simon Mignolet, to his exercise of the dark arts against Sturridge. At the end of which he has played a major role in back-to-back defensive performances of the highest calibre despite not having started a game for Chelsea since January.

There are two things to take from this. First, there is simply a late-blooming reminder here of Cole's enduring qualities as a defensive left-back. Of all England's allegedly golden generation, the swells of Baden-Baden, Cole has been arguably the most consistent, a full-back of real quality whose standards have rarely dipped, who has never looked fazed in the bigger matches, and who has enjoyed a stellar domestic and European career.

And second, he still has something to give. A few weeks back it seemed increasingly likely that Luke Shaw, playing regularly for Southampton, would go to Brazil as England's reserve left-back. Cole has now challenged this, providing evidence that he remains a high-class footballer, and more defensively sound than either Shaw or Leighton Baines, who would find his first-choice spot challenged should Cole make the cut.

Chelsea's tactics this week will be cajoled into the argument here. Some will find it hard to acknowledge the craft in Cole's back-to-back performances, given that this kind of pure defending appears to be an unfashionable art right now, seen as a kind of spoilsport pursuit, an inexplicable denying of goals, an un-YouTube-able event. Against this the fact remains that no team has won a World Cup without being able to defend, with the slight exception perhaps of the last World Cup winners, who often mitigated the need to defend by simply refusing to give the ball to the opposition.

In the end whether Cole makes it to the World Cup will depend firstly on policy: is this a squad picked with Euro 2016 in mind, or simply a pragmatic selection for the summer to come? And beyond that how do England really want to play? Cole will not maraud constantly down the left flank. But he can defend. And the evidence suggests England might end up doing quite a lot of that in Brazil, even in matches they don't lose. Either way it would be unwise to bet against Cole producing another sweat-soaked, low-fi masterclass in Manaus six weeks from now.