Captain Michael Clarke welcomed his fifth century of the year - and a national record - after carrying Australia to 440 for eight on day two of the second Test against Sri Lanka in Melbourne on Thursday.

Clarke's 106 afforded the hosts a formidable lead of 284, and saw him pass former team-mate Ricky Ponting's prolific haul of 1,544 runs in a calendar year.

Only Pakistani Mohammad Yousuf (1,788), West Indian Viv Richards (1,710) and South African Graeme Smith (1,656) have scored more runs than the talented Clarke in a dedicated 12 months.

"In regards to beating Ricky, in my eyes he was certainly the greatest batsman I was lucky enough to play with so to beat any record that Ricky holds is very special, that's for sure," said Clarke.

"Numbers have never really bothered me too much. It's nice to be making runs and leading by example as one of the leaders in the team and the captain of the team, but to me it's about winning games."

Clarke's ton was complemented by all-rounder Shane Watson's 83 and the left-handed Mitchell Johnson's unbeaten 73, which the host captain hoped would graduate to three figures come Friday.

"I would love to see Mitchell get his second Test century and then we'll be back out there bowling and hopefully we can bowl Sri Lanka out," concluded Clarke, whose side currently sport a one-nil lead in the three-match series.