Frank Lampard hopes Rennes match-winner Olivier Giroud knows just how highly valued he is at Chelsea.

The France striker's towering last-gasp header spared Chelsea's blushes on Tuesday, handing the Blues a 2-1 Champions League victory at Rennes.

Callum Hudson-Odoi's early strike had the Blues coasting until Serhou Guirassy's late equaliser left Chelsea ruing a host of missed chances.

World Cup-winner Giroud climbed off the bench to complete a dramatic rescue act however, to seal Chelsea's safe passage to the Champions League's last 16 with two Group E matches to spare.

Giroud has already been linked to a January exit as the 34-year-old aims to maintain his status as France's top marksman ahead of next summer's European Championship.

But Lampard remains hopeful Giroud appreciates just how much the Blues boss relies on him at Stamford Bridge.

"I think with Oli, it's hard to say I won't have to prove things to him, because all I have to do myself really is look game by game and try to plan to get the best for us," said Lampard.

"At the moment Tammy's in great form as well, so I have to pick on face value to get the best for us.

"I hope and I think Oli knows how much I'm happy with him and how much I rely on him in moments.

"Every player wants to play every game, it's an impossible part of my job to keep them all happy, but hopefully he knows and he feels content.

"He got minutes coming on today, and there will be games when he starts for us as well. Hopefully we keep moving forward that way."

Alfred Gomis must have thought he had sealed Rennes' draw when thwarting Timo Werner – but then the home keeper's parry looped high in the box. Giroud reacted quickest and smartest to the loose ball and buried a testing header to extend Chelsea's unbeaten run to 13 matches in all competitions.

Asked if Giroud's goal underlines just why Chelsea want him to stay at Stamford Bridge, Lampard said: "Yes, it does, and I've felt it first-hand, last year it was him or Tammy fighting for the number nine spot.

"Tammy had a great first half of the season, and then Oli in restart was fantastic.

"And the things behind the scenes, everybody kind of feels from the outside what a great professional he is and how highly-regarded he is by his team-mates and myself.

"So for him to get a goal, you saw the reaction of his team-mates, he's so professional in how he trains and looks after himself that age isn't even a factor for him.

"He's getting better with age if anything in terms of how he looks after himself.

"So he offers a lot for us and I keep saying it but the big schedule coming up and the way we play means I will rely on players.

"So thankfully for me he's a player that always keeps the right attitude if he's not playing regularly, and I know when I call upon him that he comes in as he did today."