Martin O'Neill admitted Republic of Ireland were not good enough as they held on for a 1-1 draw in their World Cup Qualifier in Georgia on Saturday.
Shane Duffy headed Ireland into an early lead, but Georgia levelled before the break and dominated possession throughout.
Although Ireland had chances to snatch victory, O'Neill told Sky Sports: "We didn't play well enough in the first half and Georgia were better than us. Second half we improved, which we had to, and it's disappointing because of the performance, but we are still in it.
"We have some very good technical players who didn't perform as well as they can."
O'Neill spoke beforehand about the need for Ireland to keep possession, but acknowledged afterwards: "We didn't do that well enough. We didn't close down strongly, and when we did have it we gave it away too cheaply, which is not a great sign.
"The game really opened up in the second half and it was end to end, but the first half we need to address. We need to do better because we are up against a talented side in Serbia on Tuesday."
The draw sees Ireland fall two points behind Serbia in Group D ahead of their meeting in Dublin on Tuesday, live on Sky Sports Football.
"I said at the beginning that any team who finishes in front of Serbia will win the group, that's the way it seems to be," said O'Neill.
James McClean, who saw a late chance saved, admitted it had been a lacklustre Republic of Ireland display.
"It's been a disappointing night," the West Brom winger told Sky Sports. "Just not good enough on the night to be honest.
"All around we weren't good enough: our passing, our energy, our defending, our finishing. They're a lot better than what people think when you look at their results through the group.
"Saying that I believe we're better, but tonight we didn't show that - all over the pitch they were better, passed the ball better. We'll have better nights; hopefully one of those will be on Tuesday."