Tourists lost two vital wickets of Sehwag and Ganguly half way thro' the second session before Sachin and VVS dug in to revive tottering innings with an undefeated 31-run stand going into tea.
Tendulkar, 0 not out at lunch, cruised to his half-century off just 77 balls. He had struck five fours and a six - a powerful clout off Hogg over wide mid-wicket. He played the Aussie seamers with caution mixed aggression and meted out some rough treatment to wrist spinner Hogg. Laxman on the other hand was his usual self pushing the ball in gaps with immaculate timing.
Sehwag struck 63 runs to steady the tottering India ship after Johnson's double-blow jolted the tourists.
Earlier, India skipper Anil Kumble won the toss and elected to bat on a batting wicket. All-rounder Pathan, promoted to open the batting in the absence of regular opener Wasim Jaffer, nicked a defensive push to wicketkeeper Adam Gilchrist off Johnson in the eighth over, and Dravid edged Johnson low to Ricky Ponting at second slip in the 24th over.
Sehwag, on 56 at lunch, left in the seventh over after the break when he snicked Brett Lee to Matthew Hayden at first slip, and Ganguly left nine overs later, lbw to left-arm spinner Brad Hogg. This is for the fourth time Hogg dismissed Ganguly in the ensuing series.
Left-hander Ganguly, who had point to prove after his exclusion from the ODI squad, disappointed the packed Oval crowd. He missed a sweep off a straight one from Hogg and Pakistani umpire Asad Rauf took unusually long time before uphelding the decision. TV replays confirmed it was a good decision.
India brought back off-spinner Harbhajan Singh for Jaffer, giving the tourists five front-line bowlers - pacemen RP Singh, Pathan and Ishant Sharma and spinners Kumble and Harbhajan.
Australia made two changes from the third Test in Perth, reincluding opening batsman Hayden, who had recovered from a hamstring strain, and Hogg for opening batsman Chris Rogers and fast bowler Shaun Tait.
Brief Scores (at tea, D-1):
India 187 for 4 (Sehwag 63, Tendulkar 55 n o, Laxman 16 n o; Johnson 2 for 53, Hogg 1 for 32, Lee 1 for 44) Vs Australia.