The tournament co-hosts opened their campaign with a 2-1 win over Bahrain earlier in the week, but the Bulgarian coach is expecting a more exacting challenge against the three-time champions.

"The second game with the Saudis will be tougher than the first game," said Kolev. "The first reason is that they know how we play and the second is because they lost points in their first game [1-1 draw against South Korea].

"They have to grab the full points against us, so for the Indonesia team it will be a tough game."

Indonesia have injury doubts over captain Ponaryo Astaman and fellow midfielder Mahyadi Panggabean, who were both replaced in the first half of the Bahrain game. A decision on their availability will be made before the match.

"No matter who plays tomorrow, they will have to play to the maximum of their ability," said Kolev, who celebrates his 50th birthday on Saturday.

"Some of the defenders made mistakes against Bahrain and I also noticed that the Saudis have very good strikers so I have told the players to be careful in the next game, especially the defenders."

With a sell-out crowd expected at Jakarta's historic old stadium, Saudi coach Helio Anjos has told his team to feed off the energy from the home fans rather than being intimidated by them.

"When I talk with the players, I always tell them not to be affected by the crowd," said the Brazilian.

"I always ask the players to play as if they were artists. The most important thing for any artist is the crowd because it motivates them to give their best.

"Since I come from a Latin country, I know what it is like to have full crowds at the stadium. I believe that it will not have a negative effect and the fans will give the team a push to give their best in the game."

Despite his team's 1-1 draw against South Korea in what was Anjos' first competitive match with Saudi Arabia, the former Sao Caetano coach is already under pressure from pundits back in the Middle East.

But after spending just 35 days with the team, Anjos is not concerned about the criticism.

"It is normal for any coach who coaches the team for only one month to have flaws in his team," he said. "However, I will try my best to fix things and put things right.

"We have had less rest than the Indonesians but I hope that we will be able to make the team as ready as we can.

"We are preoccupied with this thing and all the technical and medical staff are checking the fitness and conditions of each player."