With Ulster hosting Pool 5 bottom club Benetton Treviso this weekend, Sunday's clash at Welford Road could go a long way to deciding who remains in the running for the knockout stages.
Leicester are unlikely to have the tie all their own way as Montpellier have won their last three Heineken Cup games against English sides. Cockerill admits the French sides can be unpredictable away from home but insists they will be fully prepared for the visit of the Top 14 outfit.
"It's a difficult one with the French because they can travel to England and not be particularly interested," said Cockerill. "But then you can go to their place the week after and they will be up for the battle because they're playing at home. They're always a difficult one to read.
"But they are a good squad. Fabien Galthie is a good coach, he knows the game very well and he's got a good squad. They may well come to Welford Road with a fully-loaded team and be up for the battle.
"We will be well prepped. We need to win - we have to win. We've now got to play well enough to do that."
Leicester go into Sunday's tie on the back of four straight wins, the most recent of which was a 22-17 triumph at Gloucester on Friday night, while Montpellier have won just one of their four fixtures since losing at home to Ulster in Round 2.
Leicester have won just two of their last seven Heineken Cup games against clubs from France.
Montpellier have won their last three Heineken Cup games against English opponents.
Montpellier made just 146 tackles in their two opening games, fewer than any other side in the tournament.