Chelsea boss Frank Lampard praised Olivier Giroud for once again stepping up with his late goal against Rennes and says the striker has given him "a problem" when it comes to his team selection.

Second-half substitute Giroud headed in an injury-time winner for Chelsea in Tuesday's 2-1 victory to earn his side a place in the last 16 of the Champions League with two Group E games to spare.

The 34-year-old scored from his only shot at Roazhon Park, for what was his second goal of the campaign in his eighth outing.

Seven of those appearances have now come via the bench and the France international revealed last week he may have to leave Chelsea in January if he is to keep alive his hopes of representing his country at Euro 2020.

Lampard vowed on the eve of the Rennes match to give Giroud more opportunities, however, and the Chelsea head coach heaped further praise on the former Arsenal man after his late heroics in his homeland.

"He does things like he does tonight, he's great for us," Lampard told BT Sport. "It wasn't just his goal when he came on but his hold-up play and physicality.

"I have a problem because Tammy [Abraham] is playing well and Olivier in the restart was incredible. I have two players fighting for the position, but it's a good problem.

"He'll get his minutes because of the amount of games. You saw the reaction to his goal, and that wasn't just because it was a late winner – it shows what he does day to day and what he means to the team."

Giroud has scored six goals in 13 matches since the Premier League resumed post-lockdown in June – one more than next-best Abraham, who has played four games more.

Abraham has been favoured of late and scored in last weekend's 2-0 win at Newcastle United, with Lampard welcoming the competition to lead the line.

"They are fighting for a place in the side," he added at his post-match news conference. "But we know what a great professional [Giroud] is. To see the reaction of the team-mates showed what kind of a player he is. He always keeps the right attitude.

"We are playing every three days, maybe two days. I don't want think I have to prove to him that he will play games. Tammy is in great form as well. I hope that he knows what I want with him. He came on today and impressed."

Callum Hudson-Odoi had earlier given Chelsea the lead after being played in by a sublime pass from Mason Mount, who also won possession to start the attack from inside his own half.

Mount has now registered eight assists in all competitions since the start of last season, putting him level with Cesar Azpilicueta and Abraham among players still at the club.

The England international has had his place in the side questioned by some but Lampard feels he has more than justified his selection.

"With Mason there's been a lot of talk and any negative talk just needs to go away," he said. "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. We need to keep that competition."

Hudson-Odoi's opener and Giroud's winner came either side of Serhou Guirassy's header five minutes from time for a Rennes side on a four-match losing streak, ensuring that Chelsea can look forward to the knockout round.

"I'm very happy to qualify with two games to spare," Lampard said. "It was a really tough match, they're a very good team. 

"Their recent form doesn't reflect how good they are, it was a tough, hard-fought win."