Tottenham man Eriksen opened the scoring with a great strike. It just wasn't the result.
The video assistant referee then played a part in Australia's equaliser as match official Lahoz took a look at a handball claim against Poulsen.
"We're still in with a sniff", said Jedinak after the game. "After watching our game and the Peru-Denmark game I am pretty confident we can advance from our group".
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Danish defender Jonas Knudsen made an unexpected side trip home following the victory over Peru.
It means they must win against the point-less Peruvians on Tuesday night - and rely on France to beat the Danes - to escape the group stage.
France ended Peru's hopes of reaching the last 16 with a 1-0 win thanks to Kylian Mbappe's 34th-minute goal.More news: Neymar returns to Brazil training after injury scare
He has a total of three World Cup goals and all have been from penalties.
It was the 11th penalty of the tournament, one more than in the entire group phase in 2014.
Tottenham Hotspur midfielder Eriksen, who provided the assist for Yussuf Poulsen's victor, admitted Denmark didn't produce the attacking football that yielded 20 goals in qualifying.
"Christian is a world class player".
"It's more just composing and staying concentrated, regardless of the situation, regardless of where you're standing and regardless of what's going on around you", added Jedinak, who has converted 16 straight penalties.
Eriksen, now 26, was the youngest player at the World Cup in South Africa. He has 79 appearances for the national team and 23 goals.
But his effort wasn't enough against Australia.
Denmark coach Age Hareide said at times his team appeared exhausted.
"We lost too many balls in midfield and that caused us problems", he said.
"They work across the pitch and stay in the same shape, so it'll be hard for Eriksen to find that space but it'll be vital for Denmark to get him involved and get him on the ball as much as they can, that'll be key". "Everyone knows we've got a chance still and it'll be about making sure we prepare right and the motivation will be there I'm sure".