Garcia found the target in the 35th minute when he successfully converted from the spot, while Elano struck as late as the 90th minute, also from the spot at the Jawaharlal Nehru Stadium.
After missing the last two games, Garcia seemed to be taking Kolkata to another victory before Elano, leading the scoring chart with six goals, dashed the visitors' hopes of pulling off a win on the road.
Garcia, the Spanish defensive midfielder, made a difference in the middle and was one of the best players of the day on either side. ATK maintained their table-topper status scoring against the run of play. But it was Elano, who bagged the Moment of the Match award with his strike at the death.
The hosts were awarded the penalty after John Mendonza was brought down by ATk's substitute Kingshuk Debnath. Elano, who couldn't do anything special till that point, succeeded in beating the Kolkata goalkeeper Apoula Edel with a low shot.
Chennaiyin goalkeeper Shilton Paul was red carded for raising his left leg as he fell on the ground when Mohammed Rafi was about to take a shot at the empty goal. Chennaiyin had nine shots at the goal as against just two by the visitors.
While he may have consolidated his position at the top of scoring chart, Elano was not his usual self for most part of the match. With six minutes to go for the final whistle, Jeje Lalpekhlua, who substituted Chennaiyin's marquee manager cum coach Marco Materrazi, almost scored but his measured cross hit the upright.
After Paul was given the marching order, Gennaro Bracigiliano took on the responsibility at the post, and he failed to read Garcia. The standout teams so far in the inaugural edition of the football league, Atletico de Kolkata and Chennaiyin FC occupy the top two spots in the points table.