Brisbane, Jan 20 : "Never ever, ever underestimate" the Indians, said Australia head coach Justin Langer following their Test series loss against the Ajinkya Rahane-led side. An injury-ravaged India, fielding a second string team, on Tuesday defeated Australia by three wickets in the series-deciding fourth Test at the Gabba, a month after the Adelaide debacle where the visitors were bundled out for their lowest ever Test total of 36. India became the first team to beat Australia at the Gabba in a Test match since Viv Richards' all-conquering West Indies team in November 1988. "It was an incredible Test series and in the end there is always a winner or a loser. Today Test cricket is the winner. It's going to hurt us big time. India deserved full credit. They have been outstanding but we have learnt lessons from it," Langer told Channel 7 after the Brisbane Test. "First, you can never take anything for granted, second never ever, ever underestimate the Indians. There are 1.5 billion Indians and if you play in that first eleven you got to be really tough, don't you?" he added. The former Australia opener Langer said India put up a remarkable fightback after the Adelaide debacle especially after the ouster of big players like Jasprit Bumrah, Ravindra Jadeja and Ravichandran Ashwin due to injuries. Ashwin and Hanuma Vihari managed to eke out a draw in the third Test that kept the series level. Both players were injured after that along with frontline fast bowler Bumrah which led to India having to field debutants Washington Sundar and T Natarajan in the fourth Test. Shardul Thakur, who had played just one Test before that, was also included while Mohammed Siraj, who made his debut in the second Test, was pushed to being India's new ball bowler. "I can't compliment India enough. They haven't gone away after that first Test match which we won in three days, bowled them out for 30 odd. For them to fight back like they did is amazing, credit to them. The big lesson for us is that you can't take anything for granted. India never got away," he said. Rishabh Pant and Shubman Gill were the stars on the final day of the fourth Test in which India chased down a target of 238. Gill scored 91 while Pant was unbeaten on 89. Langer said that the latter's innings reminded him of England all-rounder Ben Stokes's 135 at Headingley during the third Ashes Test in 2019 in which he smashed 75 runs with no.11 Jack Leach at the other end to take England to victory by one wicket . "It was an amazing effort. (Rishabh) Pant's innings somewhat reminded me of Ben Stokes's innings in Headingley actually. He came in, he was almost fearless and he will be lauded because of it. It was an unbelievable innings," Langer said in his praise of the Indian wicket keeper-batsman. "I thought young (Shubman) Gill (91) batted very well. Their young bowling attack kept us under pressure throughout the match and as I said India deserve full credit." Langer also said that he was proud of his bowlers for the efforts they put in throughout the series. "From our point of view, we had the same four bowlers (Pat Cummins, Josh Hazlewood, Nathan Lyon and Mitchell Starc) who have gone hard, they have stood up and they have worked so hard but unfortunately we didn't get over the line today," he said. /IANS