An Asian Champions League goal drought is threatening to derail Sydney's campaign, but the Sky Blues may also be in imminent danger of losing key midfielder Josh Brillante.
Sydney's 1-0 loss away to Kawasaki Frontale on Wednesday means they are the only one of the 32 teams in the competition yet to score.
Like fellow A-League club Melbourne Victory, Sydney are bottom of their group after two of six games, with Australian teams again struggling to make a mark on Asia's premier football club competition.
The home team had 20 shots to two and Sydney were indebted to Andrew Redmayne for keeping them in the game with a string of saves, before the home team scored their 83rd-minute winner.
Sydney's only attempts on target were captain Alex Brosque's first-half header and Anthony Caceres' second-half long-distance shot.
"I thought our boys did extremely well, especially defensively, but we need to improve and score more goals," Corica said.
"We had maybe two good chances to score and it just comes down to finishing off, it's the final touch."
"I thought our captain had a good chance in the first half with a header.
"Maybe if he scores this goal the game completely changes."
Another concern for Corica is the possible loss of Brillante, who was left out of the starting side after it was revealed a foreign club - believed to be South Korea's Pohang Steelers - had expressed interest in him.
"There has been overseas interest in Josh which meant he wasn't in the right frame of mind for tonight's game," Sydney's Twitter feed said.
Brillante has been a key member of the Sky Blues' side in their last two successful campaigns, rarely missing games and combining with Brandon O'Neill to help shield the defence and initiate attacks.
In the other group H game on Wednesday, South Korea's Ulsan Hyundai scored a 1-0 home win over China's Shanghai SIPG.
While Sydney are running last in their group they are only three points off top spot, with each of the other teams having won a game.
"Ulsan winning it's levelled the group out, so it's quite tight up the top and we're not too far away,' Corica said.
'We need to win our next game against SIPG and to pick up three points to make this group very tight."
Sydney host Shanghai on April 10, but the second-placed A-League team return to domestic action on Sunday at home to fellow finals aspirant Melbourne City.