Yousuf, who had returned to the batting table last week in number-one position after his century in the first Test at Galle, scored only 10 and six in the second Test and, as such, he has dropped four places to fifth position in the latest rankings which were released after the conclusion of the St Vincent and Colombo Tests.
Pakistan captain Younus Khan was able retain his second position in the rankings but by conceding 12 points following scores of 0 and 82, he has fallen nine points behind Gambhir who has gone ahead of both the Pakistan batsmen without hitting a ball for the first time in his 25-Test career in which he has scored 2,271 runs at an average of over 54.
Gambhir's 847 points is relatively low for a number-one position in modern times as usually a batsman nearer to the 900-point mark goes to the top, which reflects that he has benefited from some of the other top batsman being off their peaks.
The 27-year-old left-handed opener is the first India batsman after former captain Rahul Dravid to top the batting chart. Dravid had briefly become the number-one batsman after hitting centuries in each innings (110 and 135) of the Kolkata Test against Pakistan in March 2005. Dravid had first achieved the top batting ranking in January 1999 and has been number-one for 36 Tests between 1999 and 2005.
Sachin Tendulkar is the other India batsman in the last 15 years who has topped the batting chart. He first led the table in November 1994 while last time he occupied the number-one position was in August 2002 after the Leeds Test against England. Overall, Tendulkar has been the number-one batsman for 125 Tests between 1994 and 2002.
The other India batsmen to have achieved number-one positions in their careers are: Gundappa Viswanath (seven matches in 1975), Sunil Gavaskar (46 matches between 1978-80) and Dilip Vengsarkar (17 matches between 1987-88).
Both the Test and ODI batting rankings are now headed by India batsman with Mahendra Singh Dhoni in number-one position of the Reliance Mobile ICC Player Rankings for ODI batsmen with Yuvraj Singh in second place.
However, with only 10 points separating Gambhir from third-placed Kumar Sangakkara of Sri Lanka, the top order is expected to change again, of course depending how the Pakistan and Sri Lanka captains perform in the third and final Test which starts in Colombo from 20 July.
The only other change in the top 20 is Thilan Samaraweera who has slipped one place to 21st position which has allowed Australia's Mike Hussey to return to the top 20.
Outside the top 20, Tillekeratne Dilshan has dropped one place to 28th, Kamran Akmal has fallen two places to 33rd and Misbah-ul-Haq has slipped eight places to 40th.
The only big movers in the latest rankings are Pakistan opener Fawad Alam, who has entered the table in 52nd position after his 168 on his Test debut, and Bangladesh's Tamim Iqbal whose century in the second innings has helped him rocket 22 places to 62nd spot.
There is also a change at the top of the Reliance Mobile ICC Player Rankings for Test bowlers for the first time in more than three years with Muttiah Muralidaran handing over the baton to South Africa fast bowler Dale Steyn.
Steyn had briefly joined Muralidaran in number-one position after the second Test against India in Ahmedabad in April 2008. However, Steyn had failed to go top of the table on his own after a disappointing third Test in Kanpur.
For Muralidaran, it is the first time that he has dropped to second position since February 2006. This is due to the due in part to him missing both the Tests of the ongoing series due to injury and a player loses one per cent of his ratings for every match he misses.
Others to make an upward movement are Pakistan fast bowler Umar Gul, who has gone up two places to 15th position, Bangladesh spinner Shakib Al Hasan (up by four places to 33rd), Sri Lanka spinner Rangana Herath (up by four places to 46th), West Indies fast bowler Darren Sammy (up by 12 places to 53rd), Pakistan off-spinner Saeed Ajmal (up by 22 places to 54th) and Sri Lanka fast bowler Nuwan Kulasekara, who has rocketed 28 spots to 56th place.
Those who have failed to maintain their rankings include Sri Lanka spinner Ajantha Mendis, who has slipped one place to 29th spot, Bangladesh captain Mashrafe Mortaza, who has dropped two places to 40th position, and Pakistan fast bowler Mohammad Aamer, who has fallen 10 places to 72nd position.
Jacques Kallis continues to lead the Reliance Mobile ICC Player Rankings for Test all-rounders with Mitchell Johnson of Australia in second, New Zealand's Daniel Vettori third.