Michael Clarke overcame a serious back injury to reach 98 as Australia moved to 6-423 before rain again interrupted day two of the first Test against India on Wednesday.

Clarke had progressed to 85 at lunch, which was taken early at Adelaide Oval because of a rain delay.

Steve Smith scored two runs off the first delivery of the second session to bring up his fifth Test ton and is unbeaten on 103.

Smith made his way to the No.408, painted on the turf as one of many tributes to Phillip Hughes, pointed his bat to the sky and hugged Clarke.

Clarke helped himself to a pair of boundaries off legspinner Karn Sharma in the following over, but rain returned soon after to send players scurrying off the field.