Chennai, Dec 30 (PTI): Indian captain Mahendra Singh Dhoni's heroic unbeaten century under pressure went in vain as arch rivals Pakistan held their nerve to clinch the first one day international with a comfortable six-wicket victory in a low-scoring contest here today.

India posted 227 for six after recovering from a precarious 29 for five one stage but that turned out to be insufficient for the Pakistanis who rode on Nasir Jamshed's unbeaten century to overhaul the target with 11 balls to spare and take a 1-0 lead in the three-match series.

Dhoni played a captain's knock with an unbeaten 113, his 8th ODI century, to script a brilliant Indian recovery after left-arm pacer Junaid Khan (4/43) exploited the overcast conditions to rip through the top-order and leave the hosts gasping for breath within the first 10 overs.

The Indian captain found an able ally in Suresh Raina (43) first and then Ravichandran Ashwin (31 not out) to take the score beyond the 200-run mark which looked doubtful at one stage following the top-order collapse.

Dhoni and Ashwin put on a record seventh wicket partnership of 121 runs but the Indian captain's superlative knock off 125 balls lost much of its value as the Pakistani batsmen went about the task of chasing down the target without taking too many risks.

Younis Khan (58) and Shoaib Malik (34 not out) were the other notable performers for Pakistan.

The Pakistani innings started on a disastrous note as ODI debutant Bhuvneshwar Kumar produced a beauty to get rid of Mohammed Hafeez with the very first delivery of the Pakistan innings.

The ball came back sharply after pitching as Hafeez didn't offer a stroke only to find his off-stump knocked back.

The youngster got rid of Azhar Ali a few overs later to reduce the visitors to 21 for two. But the experienced Younis Khan and Nashir steadied the Pakistan innings with a solid 112-run third wicket partnership.

Both Jamshed and Younis benefitted due to some horrendous decisions given by the Indian umpire S Ravi. Jamshed was lucky to get a reprieve on 24 when an inside edge was caught by Virender Sehwag in first slip off Ashwin but Ravi turned down the appeal.

Ravi also negated a plumb leg before decision against Younis when the right-hander missed a delivery from Ashwin in his bid to play the sweep shot.

Younis returned to the pavilion when Ashwin latched on to a low catch off Ashok Dinda, a decision which was referred to the TV umpire by on-field umpire Billy Bowden. But by that time, the visitors were already in a good position and just needed to bat sensibly to reach the target.

Jamshed, who grew in confidence as the innings wore on, was dropped by Yuvraj Singh when on 68 off Dinda much to the disappointment of a sizeable holiday crowd at the Chepauk.

Just when Pakistan seemed to be cruising along comfortably, Ishant Sharma enlivened the proceedings to some extent by getting rid of captain Misbah-ul Haq (16) with a slower ball which knocked down the off stump.

It was Malik, who hit the winning runs with a pull towards deep mid-wicket boundary off the first ball of the penultimate over.

Earlier, put into bat, India plunged into trouble straightaway with Gautam Gambhir (8), Virender Sehwag (4), Virat Kohli (0), Yuvraj Singh (2) and Rohit Sharma (4) returning to the pavilion in quick succession as Junaid got the ball to swing under overcast conditions.

The Pakistani pacers took advantage of the moisture on the track and troubled the top-order batsmen with the new ball. Once the ball got a little older, Dhoni and Raina applied themselves and started rebuilding the Indian innings.

The two teams will now travel to Kolkata for the second ODI to be held on January 3 while the third and final match will be staged at the Ferozeshah stadium in New Delhi on January 6.

Pacer Junaid had justified his captain Misbah-ul-Haq's decision to bowl first in damp conditions with struggling opener Sehwag becoming Junaid's first victim.

The Delhi batsman, considered a game-changer for his ability to take the attack to the opposition, swung it Pakistan's way after slogging for 11 balls to get four runs.

Sehwag was castled by a Junaid delivery that came in a shade after pitching.

The big four of the Indian batting order were all bowled, three of them by Junaid, who seemed unplayable getting the ball to move appreciably both in the air and off the pitch.

The proverbial promising batsman of the side, Rohit added another one to his growing list of failures, becoming Junaid's fourth victim after scratching around for 14 deliveries for his four runs.

Rohit's last six ODI innings now read a disappointing 4, 4, 4, 0, 0 and 5. In fact, the top five managed to pull off just two fours for the team.

At 29/5 in a little less than 10 overs, India were staring firmly down the barrel before Raina and Dhoni came together to repair the innings slowly and steadily.

The duo cautiously added 73 runs for the sixth wicket and defied Pakistani bowlers for a good 23 overs.

Dhoni got a life on 16 when in the 26th over rival skipper Misbah-ul Haq dropped him at midwicket of Mohammed Hafeez's bowling and the Indian, who smashed seven fours and three sixes, made it count.

Dhoni was suffering from dehydration and also battled cramps towards the end of India innings.

Meanwhile, Raina's patient innings came to an end when he lost his leg stump to Hafeez. But Dhoni was unfazed and, in fact, accelerated from that point, reaching his fifty with a whip over midwicket boundary off Umar Gul.

For a man not exactly known for solid technique, Dhoni was the lone Indian batsman to smash spin ace Saeed Ajmal for a six. A new ball had to be sought to replace the one which went out of the ground.

He also brought up his hundred in style, hoicking Irfan over cover in the 49th over, which produced 21 runs with Dhoni doing most of the scoring. For Pakistan, Junaid was the most successful bowler, grabbing 4/43 in his nine overs.

This was the first match played under the new ICC rules.

Under these rules, one new ball was used at each end, bowlers were allowed two bouncers an over, there was no batting Power Play, the bowling Power Play was completed before the 40th over, and at no stage in the innings more than four fielders were allowed outside the 30-yard circle.