"Today it's my turn to tender a slight apology," said Anand.
"The position we got after move 12 is a very sharp one. I have studied it in the past, it's very very complicated and I had not really expected it. That's clear," he said at the post-game conference at the Hyatt Regencey hotel.
The opening move of the second game today was a big success for Carlsen and it was a great pull back by the Norwegian after Anand had got an easy draw as black in the first game Saturday.
"I will not talk too much about the opening move. I think the critical point was on move 18 when Vishy could have tried but black seemed to be doing fine," world number one Carlsen said.
Anand said things might have become risky for him after Carlsen's opening surprise coming in the form of a Caro Kann defense.
"I had to decide whether to fly blind because it's clear that he would have been into more details. I decided to go for a slightly solid line, a slightly prudent decision today, essentially after the queen exchange there is nothing much happening," said the five-time champion Anand.
Anand, however, said the battle royale that has thus far produced just 41 moves in the two games would only get better.
"We both have a little information now as to what the other person is trying, I am sure it will get interesting," the local hero said.
Asked about the preparation for this game's opening move, Anand said, "I was trying to recollect all sharp variations around move 13-15, trying to figure out what he might be aiming for before he took the path to equality."