Joe Root held a brilliant slip catch to dismiss Marnus Labuschagne as Australia ground their way to 115-2 at lunch on the second day of the fifth and final Ashes Test at The Oval on Friday.

Labuschagne was the only man out in an attritional morning session that ended with Australia still 168 runs behind England's first-innings total of 283.

Opener Usman Khawaja dropped anchor to be 47 not out off 152 balls, with star batsman Steve Smith, adding some impetus, unbeaten on 13. 

Australia, as the holders, are already assured of retaining the Ashes at 2-1 up, and only need to avoid defeat at The Oval to secure their first Test series win away to England in 22 years.

But in their desire to deny England a breakthrough in London the innings stagnated.

Labuschagne, fresh from his hundred in last week's rain-marred drawn fourth Test at Old Trafford, was two not out overnight.

But he took a further 59 balls to score seven more runs before he was superbly caught in the slips by Root off fast bowler Mark Wood.

Australia resumed on 61-1, with left-hander Khawaja 26 not out off 75 balls -- a marked contrast to England's frenetic 'Bazball' approach.

The tourists held firm in a tense first hour on Friday.

But Labuschagne eventually fell when he edged a full-length ball from express quick Wood and Root held a brilliant one-handed catch diving to his left at first slip after Jonny Bairstow had not moved for a chance that belonged to the wicketkeeper.

That left Australia on 91-2, with Labuschagne failing to reach double figures in an 82-ball innings.

But new batsman Smith upped the tempo with two superb straight-driven fours off successive deliveries from veteran paceman James Anderson, who turns 41 on Sunday.

England were a bowler light after it was announced Moeen Ali would remain off the field with the groin injury the off-spinner suffered while batting on Thursday.

Ben Stokes's longstanding knee problem has effectively reduced the England captain to a specialist role as a batsman during the series.

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