Mancini saw his side slip to a 2-0 loss in Jeddah on Thursday against a Japan side that has dominated Asia's third round of preliminaries to leave the Saudis playing catch-up in the race for World Cup qualification.
Saudi Arabia are looking to book a spot at a third consecutive World Cup - and seventh in total - with Mancini telling his players they cannot rely on historic performances to confirm their passage to North America in two years' time.
"We don't live in the past, the important thing is to qualify regardless of the ranking," said Mancini, who took over as the long-term replacement for Herve Renard in August 2023.
"Three years ago the situation was different. Maybe the players were playing more or were younger. We have to deal with the current situation."
Renard resigned in March 2023 to take charge of France's women's team and moves to strengthen the Saudi Pro League by authorities since then have seen a significant influx of highly paid foreign stars shift to the country in recent seasons.
Their arrival, which comes with clubs allowed to sign as many as 10 non-Saudi players and field up to eight in each SPL match, has left Mancini overseeing a group of players who are often lacking regular game time.
"The only problem we have, three years ago all the Saudi players played every game," said Mancini. "Today, 50, 60 per cent don't play in the game and this is the only problem that we have."
Saudi Arabia host Bahrain on Tuesday, looking to return to winning ways with Mancini's side level on four points with their visitors and Australia. Indonesia are a further point adrift with China bottom of the group with zero.
Only the top two finishers are certain to qualify for the finals in North America with the third and fourth-placed teams advancing to a further round of preliminaries.
