NEW DELHI (AFP) - Gautam Gambhir and Venkatsai Laxman hammered double-centuries to put India in complete control on the second day of the third Test against Australia here on Thursday. Opening batsman Gambhir struck a career-best 206 while the stylish Laxman remained unbeaten on 200 as the hosts posted a massive 613-7 before declaring their first innings midway through the final session. Australia were cautious in their reply, reaching 50-0 at the close with Matthew Hayden on 16 and Simon Katich on 29. The day belonged to the Indian batsmen, who thrived in good batting conditions and set their side up for a series-clinching win. The hosts lead the four-Test Border-Gavaskar series 1-0 after winning the previous match in Mohali by 320 runs. The opener in Bangalore ended in a draw. "I just tried to play the ball on merit," Laxman told reporters at the end of the day's play. "I did not take too many risks because it was important from the team's perspective to put up a big score in the first innings. When I made the 100, I decided not to just throw it away and carry on for a bigger score." Gambhir, 149 overnight, struck 26 fours and a six in his knock that spanned nearly nine hours while Laxman heaped further agony on the tourists with his 301-ball innings studded with 21 fours. Laxman, 33, reached the 200-run mark with a two off Michael Clarke and also completed 2000 runs against Australia in the process. It was his second double-century against Australia after his career-best 281 in the 2001 home series at Kolkata. Laxman shared a 278-run stand with Gambhir and another 98 runs with skipper Anil Kumble (45) who must be pleased with his decision to bat first on a flat Feroz Shah Kotla track. It was the first time that two batsmen have scored double-centuries in an innings for India. There was little joy for the tourists, who toiled for two wicketless sessions before tasting some success when Shane Watson accounted for Gambhir and Mahendra Dhoni (27) and Katich sent back Sourav Ganguly (five). A desperate Ricky Ponting brought himself into the attack but without much luck as the Indians made batting look easy. It was Watson who gave his team the breakthrough when Gambhir inside-edged onto his stumps but by then the damage had already been done. Paceman Stuart Clark, who failed to bag a wicket from his 33 overs, praised the Indian batting, especially Laxman's innings. "We tried everything but they batted very well," he said. "Laxman is very wristy and he was just very good today. He pulled the ball very well and got on top of us. He got the momentum going for the Indians. We just need to bat well now and post a reasonable total." Stuck for 11 balls on 99, Laxman reached his 13th century and sixth against Australia with a cover-driven four off leg-spinner Cameron White. Laxman, who has a knack of playing big innings against Australia, and Gambhir denied the tourists any success in the morning session, putting on 97 runs off 26 overs after resuming on 296-3. Playing in his 99th Test, Laxman used his wrists beautifully to pull and drive the bowlers on both sides of the wicket. Left-arm paceman Mitchell Johnson finished with the best figures of 3-142. The fourth and final Test will be played in Nagpur from Nov 6-10. SCOREBOARD INDIA, 1st innings: (overnight 296-3): G. Gambhir b Watson     206 V. Sehwag lbw b Lee     1 R. Dravid c Hayden b Johnson     11 S. Tendulkar c Haddin b Johnson     68 V. Laxman not out     200 S. Ganguly c Ponting b Katich     5 M. Dhoni c Haddin b Watson     27 A. Kumble lbw b Johnson     45 Z. Khan not out     28 EXTRAS: (b6, lb8, nb6, w2)     22 TOTAL: (for seven wickets decl.)     613 Fall of wickets: 1-5 (Sehwag), 2-27 (Dravid), 3-157 (Tendulkar), 4-435 (Gambhir), 5-444 (Ganguly), 6-481 (Dhoni), 7-579 (Kumble) BOWLING: Lee     30-2-119-1 (nb2) Clark     33-9-69-0 (nb1, w1) Johnson     32-4-142-3 (w1) Watson     20-4-66-2 (nb3) White     15-1-73-0 Clarke     14-0-59-0 Katich     15-3-60-1 Ponting     2-0-11-0. Overs:     161 AUSTRALIA, 1st innings: M. Hayden not out     16 S. Katich not out     29 EXTRAS: (b4, nb1)     5 TOTAL: (for no loss)     50 BOWLING: Zaheer     4-2-9-0 Sharma     4-1-9-0 Kumble     4-0-17-0 (nb1) Mishra     3-0-11-0. Overs:     15 Toss: India Umpires: Billy Bowden (NZL) and Aleem Dar (PAK) Third umpire: Suresh Shastri (IND) Match referee: Chris Broad (ENG)