Serbia boss Dragan Stojkovic felt his team should have "been smarter" in trying to see out their game against Cameroon.
Stojkovic's side were in the driving seat after coming back from 1-0 down to lead 3-1 with 26 minutes to play, only for the introduction of Vincent Boubakar to transform the game.
The Al Nassr striker reduced the deficit after 64 minutes, running on to Jean-Charles Castelletto's through ball before producing an impudent scoop over Serbia goalkeeper Vanja Milinkovic-Savic - the goal given after a VAR check.
He then turned provider two minutes later, escaping down the right before crossing for Eric Choupo-Moting to fire in and salvage a 3-3 Group G draw at Al Janoub Stadium.
Stojkovic rued what he felt were two defensive lapses that allowed Cameroon to claim a point.
He said: "We controlled the match and played the way we can but these two mistakes were decisive. This should not happen but due to the fatigue and a lack of concentration it's a draw. We should have finished the match in a smarter way."
Both sides have a point from their two games and will keep a close eye on Monday's other Group G clash between Brazil and Switzerland to understand what they need to do on matchday three.
"We have a chance," added Stojkovic, whose side meet Tite's men on Friday. "We seem to like the difficult road in order to achieve a goal.
"We have to be more concentrated, especially in defence. Such mistakes should not happen or repeated any more."
Cameroon boss Rigobert Song, who left goalkeeper Andre Onana out for disciplinary reasons, was delighted by his side's determination to hit back from what seemed a lost cause.
"That’s part of our DNA," he said. "It was missing in the first match [against Switzerland] but we tried to show it today.
"What was important for this match was to show that fighting spirit, that great determination and that’s what we saw in a very committed performance."
Aboubakar, named man of the match even though he only came on in the 55th minute, took inspiration from Morocco's 2-0 defeat of Belgium on Sunday.
He said: "We saw how Morocco played and we realised you have to play with great determination if you want to win games at this tournament.
"When I came on, I tried to enjoy it and tried to make the right runs on the last defender and they found it hard to follow me."
Boubakar is the Cameroon captain but made light of being omitted from the starting line-up for both games in Qatar so far.
"Being captain is not a big deal," he added. "When I play for Cameroon I try to do my best and to win the game. Whoever is captain it doesn’t really matter. You have to play for the team."