Northern Ireland manager Michael O'Neill says Thursday's World Cup play-off in Italy is "a big opportunity and it's important we don't waste it".

With 57 places between the sides in the world rankings, Italy will be favourites to win the semi-final in Bergamo.

But the four-time World Cup winners have not qualified for the tournament since 2014.

Thursday's victors will then travel to either Wales or Bosnia-Herzegovina for a shot at joining Canada, Switzerland and Qatar in Group B at the finals.

If Northern Ireland qualify, it would be a first World Cup appearance in 40 years.

"The important thing for us is to play the game and not think about what's at stake," O'Neill said in his pre-match press conference on Wednesday evening.

"The expectation clearly lies with the home nation and the big nation, which is Italy.

"We have to not be intimidated by the reputation of the players that they have, and I don't think we will be.

"We have a lot of young players who are going on an upward trajectory in their careers, and tomorrow night is just another step."

In a squad update, O'Neill was "optimistic" Ali McCann would be fit for the game after the midfielder missed Preston's final match before the international window with an ankle injury.

O'Neill added his young squad, the majority of who will be playing the biggest games of their careers against Gennaro Gattuso's side, will have "no fear", and said quotes from the Italian media have helped him get that message across.

"It is important that we are aware of emotional side of the game for the opponent as well," he explained.

"We've discussed that with the players and we've thankfully been able to lift some quotes from your own [Italian] media that we've been able to use to demonstrate the pressure that the players are under, so thank you for that.

"But, at the end of the day, that's a little bit of a sideshow. The game will be played over 90 minutes and possibly longer.

"How they deal with all that will be a big factor in the game and hopefully we can make the game very difficult."

Key Italy midfielder Sando Tonali is expected to be fit, despite missing Newcastle United's derby loss at home to Sunderland on Sunday.

Inter Milan defender Alessandro Bastoni remains a doubt, but he played a small role in training, and Gattuso said striker Gianluca Scamacca "is a little further behind".

In his press conference, Gattuso - a World Cup winner as a player in 2006 - brought up Northern Ireland's style of play and said Italy will have to adapt to a "direct approach".

In response, O'Neill said "we don't consider any of that" when it came to setting his team up.

"They really believe a great deal in what they're doing, with the second balls and they like to play direct, vertical football," added Gattuso.

"They are certainly a team that when they get players into the box, both with crosses and from dead-ball situations, they're incredible."

Gattuso acknowledged the running power and energy of their opponents, but said being direct was "their main skillset" and "where they will cause us the most problems".

"I haven't seen a team that's necessarily going to be keeping the ball and dragging you out of position in the middle of the park," he added.

"They play very direct and everything that they do, they do it in an impressive fashion."