* Timani replaces the injured McMahon
* Moore to equal George Smith on 111 caps
LONDON, Oct 6 (Reuters) - Number eight Lopeti Timani will make his first start for Australia as a replacement for the injured Sean McMahon when the Wallabies finish their Rugby Championship campaign against Argentina at Twickenham on Saturday.
McMahon was injured in the 18-10 loss to South Africa last weekend, affording Timani a first start after he made his debut off the bench in the 36-20 home win over Argentina last month.
In the only other change to the starting line-up, lock Rory Arnold was recalled to the run-on side in the place of Rob Simmons, with second row partner Adam Coleman switching to the number five jersey.
The duo will form the tallest lock pairing in Australian test history -- Coleman standing at 2.05 metres and Arnold at 2.08m.
Cheika has again named an extended bench and will omit one player before Saturday.
Should number eight Leroy Houston take his place among the replacements, he will be in line for a Wallaby debut as the only uncapped player named in the squad.
Fijian-born wing Sefa Naivalu, who became eligible for the country last month and made his debut in last weekend's loss to the Springboks, is again named on the extended bench.
Captain and hooker Stephen Moore will equal George Smith's mark of 111 test caps and become the joint-fourth most capped Australian test player in history.
The match has been moved to Twickenham by SANZAAR in an attempt to widen the interest and audience for the Rugby Championship in the northern hemisphere.
It is the same venue where the teams met in the semi-finals of last year's World Cup. Australia triumphed 29-15 before losing the final to New Zealand.
Team: 15-Israel Folau, 14-Dane Haylett-Petty, 13-Samu Kerevi, 12-Bernard Foley, 11-Reece Hodge, 10-Quade Cooper, 9-Will Genia, 8-Lopeti Timani, 7-Michael Hooper, 6-Dean Mumm, 5-Adam Coleman, 4-Rory Arnold, 3-Sekope Kepu, 2-Stephen Moore (captain), 1-Scott Sio.
Replacements (one to be omitted): 16-James Hanson, 17-Tom Robertson, 18-Alan Alaalatoa, 19-Kane Douglas, 20-Scott Fardy, 21-Leroy Houston, 22-Nick Phipps, 23-Tevita Kuridrani, 24-Sefa Naivalu. (Reporting by Nick Said)