Clarke said on Friday he was confident that Australia can regain the top spot.
“When we left England we were still the number one-ranked team in the world but because of other teams playing, we've slipped back down to four,” Clarke told a press conference.
“But to me it's about playing really good consistent cricket all around the world and I know we'll get back to being number one,” said Clarke.
Australia is now ranking behind England, South Africa and India while in the T20 rankings Australia is at ninth position, below New Zealand and Bangladesh too.
Talking about ODI series with Pakistan, he said, “No doubt Pakistan's on my mind but our focus as a team has been on Afghanistan. After Saturday's game we'll sit down then and look at the Pakistan side.”
“Pakistan also know the conditions well and these are pitches where, as the game goes on, there'll probably be a little bit more spin,” he added.
Aussies will take on minnows Afghanistan in Sharjah on Saturday. It will be the first ever match between the two countries.
This will be followed by a series between Pakistan and Australia in Sharjah, Dubai and Abu Dhabi.