Rennes 1-2 Chelsea: Olivier Giroud proves Frank Lampard’s side are ready to challenge this season

For all the talk about academy graduates and multi-million pound signings, it was an unsung cast member that provided the telling act in Chelsea’s latest challenge.

Olivier Giroud wasn’t just second favourite as the ball plummeted to the turf in Roazhon Park, he was fifth favourite amid a sea of red shirts. Two defenders instinctively ran to the line to protect goalkeeper Alfred Gomis, on the floor having denied Timo Werner, while Gerzino Nyamsi and Hamari Traore gawped. Giroud charged across, hurled himself into the air and thundered a header – a header he had no right to win – into the net to snatch victory at the death.

Chelsea had been cruising for so long in the Champions League Group E encounter. Mason Mount had delivered a statement performance in midfield, robbing Jeremy Doku and sending Callum Hudson-Odoi scuttling through on goal to score. Not only that but he outshone Eduardo Camavinga, one of Europe’s hottest properties turning heads at Real Madrid. Just look what Lampard, one of his generation’s great midfielders, thought about it.

"I'm really pleased. With Mason there's been a lot of talk and any negative talk just needs to go away, said the Chelsea manager.

"I've been lucky enough to be closer to him and what he did at Derby and last season has been outstanding. I'm not going to undermine the quality he has and when we have two number eights he's got all the qualities - I think he can get more goals and assists. The pass for Callum Hudson Odoi's goal was top class.

"I actually don't speak to him too much. We have a good relationship, not as close as some think. He knows I'm here if he needs any guidance but it's the social media world, in the modern day world we all have opinions and want different things from players. It should only be what I think, the players think and proper Chelsea fans think of him. The conversation just needs to move on, there's nothing to make of it."

Hudson-Odoi had teased the left side of the Rennes defence with smart runs and quick passing, and took his goal with composure solely lacking on the other flank. Tammy Abraham was hard-working, if not spectacular, in leading the line. If Lampard’s first season was about sieving down to the best youngsters, then Mount, Hudson-Odoi and Abraham – plus Reece James, rested for this clash – are worthy survivors.

Fears that they would be replaced by the new recruits have so far proved unfounded and while we shouldn’t read too much into it, it was hard not to notice that the trio were already wrapped up among the substitutes when Serhou Guirassy headed Rennes level on 85 minutes.

Timo Werner, the most high-profile of the summer arrivals, again dazzled with his quick footwork and movement, but his finishing remains askew. The German’s long-term future may well be in the spot Abraham currently occupies, but until he adds a clinical edge to his promise, it is not yet time for that promotion.

Thiago Silva again impressed alongside Kurt Zouma – the Brazilian continuing to prove that he remains very much in his pomp at 36 – as Chelsea were rarely threatened at the back. It was his passing with Zouma that sparked the first big chance, which culminated in Werner inexplicably blazing over from Hudson-Odoi’s teasing cross.

But it was Edouard Mendy who delivered the standout performance among the new recruits. As Pete Sharland pointed out in a recent Eurosport article, it has long been Lampard’s belief that his team’s poor defensive record was not necessarily indicative of the whole team. Now those views have been justified. Mendy made a fine close-range stop from Nyamsi before juggling the ball into his grasp, but was powerless to prevent their equaliser.

Still, that was perhaps the most impressive aspect of Chelsea’s win – how they responded to the setback. That was embodied by Giroud, fully aware that his minutes will be limited this season, carving a winner out of desire. To win trophies, it not only takes established names, but the unsung glue around them. On Tuesday, that was Giroud.

It was supposedly too early for Lampard’s Chelsea to mount a sustained challenge in Europe and the Premier League this season. A season to bed in the youth, a season to bed in the elites, then it begins. But the signs are that Chelsea may be able to bring that timeframe forward a year – and their match against Tottenham at the weekend will give another indication to their ambitions…