Sri Lanka captain Kumar Sangakkara believes not having the referral system in place for the series against India cost his side dearly.

Sri Lanka crashed to defeat in the final Test in Mumbai and slipped from second place to fourth in the International Cricket Council's rankings by losing the three-Test series against India 2-0.

Opener Tillakaratne Dilshan was on the wrong end of controversial decisions in both innings of the final Test in Mumbai, replays showing the batsman should have been given not out on both occasions.

The referral system is in use for West Indies' tour of Australia currently in progress but has been heavily criticised by players from both teams.

Sangakkara, however, is in favour of the system.

"This series is probably the best advertisement for having the review system," Sangakkara said.

"When decisions cost us over 500 runs and a lot of wickets, it always puts lots of pressure on any side.

"Not to have the review system when every other side in the world is playing with the system and when the ICC said all sides would play with the review system, it becomes an extra handicap.

"That handicap cost us a huge amount of runs in this Test and in the previous match in Kanpur."

Sangakkara, however, admitted India were the better team.

"We accept the fact that we were outplayed and out-bowled," he added.

"Two-nil is a realistic scoreline the way the Indians played and the way we played, especially in the last two Test matches.

"But we are a better side than the scoreline suggests."

India captain Mahendra Singh Dhoni, who missed the series in Sri Lanka when the system was trialled last year, indicated he was not in favour of the system.

"I think it is very difficult to say anything on it as I have not played in a single series that had the review system," he said.

"But I don't think it is 100% foolproof. It is not like a vehicle which is 100% bulletproof.

"If you are travelling in one of those vehicles, you would want it to be either 100% bulletproof or nothing at all.

"You don't want to try something that's not foolproof."