Marcello Lippi said the gap between his China team and the world's leading sides remained significant after they lost 4-0 to Colombia on Tuesday.
It was China's second defeat in a row after they were beaten 2-0 by Serbia last week, but the Italian World Cup-winning coach felt the games had been beneficial.
"From the performance we could see the gap is all round," he told reporters. "We still have a long way to go.
"If the opponent was an Asian team, we may have a gap but it would be small. We need to get to the bottom of where we are and have the right attitude towards that.
"We prefer to play strong teams. Games like this have more value in terms of improving ourselves. It doesn't mean much if we always play weaker sides."
He praised Colombia as "very good" and said facing them would "give the players an idea of the gap between them and the top teams."
Lippi was also impressed by the contribution of Shanghai SIPG winger Wu Lei, saying: "He was in very good shape. He has been quite outstanding recently in both the club team and the national team.
"The attacking quality is acceptable. In the last match we created three or four chances, and in this game Wu Lei had a one-on-one opportunity.
"However, when facing teams of this level, we need to fight with strong, integrated power because the opponent is much stronger and we need every one of us at our best."