Nigeria head to Bloemfontein's Free State Stadium looking to get off the mark after their opening 1-0 defeat to Argentina, while Greece, who slumped to a much-criticised 2-0 loss to South Korea, will chase their first ever World Cup points.
"It is quite possible that we do some changes for the game tomorrow. You will hopefully be curious but you have to wait until tomorrow," a relaxed Lagerback told reporters on Wednesday.
The Swede, whose impact as coach has won many fans in Nigeria after just over four months in charge, could bring in strikers Peter Odemwingie and Obafemi Martins after both impressed as substitutes against group favourites Argentina.
"I feel very positive, especially as the players have reacted so well after the game," Lagerback, whose squad have no injury worries, added.
"I am really looking forward to it, we probably must win it to go through to the second round. I think it is a positive challenge."
The 61-year-old has reasons to be confident. His team's attacking style poses a huge threat to a defensive Greek side never to have scored a World Cup goal, while all of Nigeria's previous tournament wins have come against European opposition.
Nigeria's brave and energetic performance against Diego Maradona's Argentina was well received back home with many calling for Lagerback to extend his stay beyond the tournament.
"I have heard rather positive things have been said about the Super Eagles. If we can live up to the expectations of those fans I am very happy about that," Lagerback said, adding that he had not yet discussed post-World Cup plans.
AFRICAN PRIDE
Africa's much-celebrated inaugural World Cup has been touted as boosting continental solidarity and striker Chinedu Obasi told reporters that traditional rivalry between nations had been put aside.
"I don't think there is any competition," the 24-year-old said.
"This is the first time an African country has hosted the World Cup, it means a lot to the players not just to play, but for history to be part of the competition."
