Gordon Strachan reckons Celtic's most important Champions League fixture is against Atletico Madrid.
The Hoops have also been drawn in a group with Feyenoord and Lazio but the former Parkhead boss feels both games against the LaLiga club will decide their fate.
And he pointed to Scotland's recent victory over Spain in Euro 2024 qualifying as a comparison to what Celtic have to face.
He told Gambling Zone: "What Celtic need to do to give themselves a chance in the Champions League is to somehow pick up that big result against Atletico Madrid because they are probably the best side in the group.
"In many ways, it’s a little bit like Scotland; we got the big result against Spain in the European qualifiers.
"To get through these group stages, you need to get a big result against one of the biggest teams and, if it is the best team, then you’re giving yourself a brilliant chance of being in the draw for the last 16."
"It is going to be a tough test. They will need all of their best players back, fit, and available – I do think that with Celtic’s best XI they can give each of these teams a game.
Strachan also maintained that the Scottish champions must be disciplined in all of their fixtures.
He feels the games might not be the most entertaining fixtures and that Celtic will have to work hard.
"There isn’t a team in the group like Manchester City, Real Madrid or even Arsenal. Atletico Madrid and Lazio are hard-working, disciplined teams," he continued.
"I don’t think we’ll see spectacular games of football because of the opponents. Atletico Madrid are experts at wearing teams down, grinding teams down.
"Lazio are the same. Celtic like to play football, but against those two teams the players need to go into them with an understanding that they are going to be hard fought battles.
"It will be hard work to beat them because of the way they set-up. They just need to get something out of them.”
