Jadeja's seven wickets, including a first-innings six-for, in the second Test against Australia helped him occupy the top rank and assured India the No.1 spot in the ICC Test Team rankings for the annual April 1 cut-off.
He shares the top spot with Ashwin, whose eight-wicket haul took him past Bishan Bedi as the fifth-highest wicket-taker for India in Tests with 269 scalps. However, Ashwin's poor returns with the bat - 20 in the last four innings - meant he has dropped behind Shakib Al Hasan on the list of Test allrounders.
The last time two bowlers shared the No.1 rank was in April 2008, when Dale Steyn and Muttiah Muralitharan were at 897 points. Jadeja and Ashwin are currently at 892 points each, and lead Australia's Josh Hazlewood at No. 3 by 29 points.
In the rankings for Test batsmen, Virat Kohli lost his second spot to Joe Root after managing only 40 in his last two Tests. Steven Smith maintained his reign at the top for the 77th Test, edging past Ricky Ponting's 76 matches as the third longest stint at the top among Australians after Steve Waugh (94) and Don Bradman (93).