England resumed hoping they would not pay a high price for the catches they dropped last night, to reprieve Clarke (90no) and his sixth-wicket partner Brad Haddin.
Clarke, of course, had the opposite agenda - and it was he who prevailed in the first hour as Australia, already 1-0 up in this series, moved quickly from 273 for five to 339 without further loss.
The Australia captain had fortune on his side, with his first scoring shot on a cloudy morning.
He tried to impose himself immediately against Monty Panesar, from the left-arm spinner's first delivery, and squirted two runs just over and wide of cover to complete his 100-ball 50.
It was the fourth half-century of the innings, but Clarke might easily have gone without addition to his overnight score after failing to get to the pitch and chancing his arm nonetheless.
There were precious few more false shots, however, as he and Haddin accelerated past a 50 stand.
Clarke targeted Panesar in particular, forcing Alastair Cook to switch to Graeme Swann after four overs which cost 22 runs.
Haddin's first runs of the morning had taken him to 1,000 against England, but he was largely content to allow his captain to make the running - to significant effect.
Quicker reactions in the field might twice have helped England see off the wicketkeeper-batsman on 18 and then 30, though.
Michael Carberry was unable to deliver the right throw for a possible run-out after a quick single to short third-man, and then Panesar could not make enough ground to take the catch after a faulty hook at James Anderson.
Both teams and the crowd observed a minute's silence before start of play, and the players took the field wearing black armbands, in tribute to former South African president Nelson Mandela who died on Thursday.