Stand-in captain Steve Smith says his understrength Australian squad must treat its opening ICC Champions Trophy match against England as a knock-out match. Australia begins its campaign in Lahore on Saturday night AEDT without star pace trio Pat Cummins, Mitchell Starc and Josh Hazlewood at its disposal for the tournament. Smith said the world champions needed to avoid making slow start to the Champions Trophy, stressing the importance of defeating England. "We know that sometimes in those big tournaments, in World Cups for instance, it takes us a little while to get into our groove, which we've done in the last few," Smith said. "But we know with Champions Trophy it's a shorter format. "You're only playing three round games, so you have to be switched on from the first one. "Our message to the group is, essentially, it's a quarterfinal to begin proceedings and, hopefully, that can bring the best out of our players." Smith offered a vote of confidence in his fast-bowling options, which include Sean Abbott, Nathan Ellis and Spencer Johnson. "There's always pressure when you're playing in international events and big tournaments," he said. "It's clear we're obviously missing a few of our gun fast bowlers, but we're not worried about that. "We're thinking about what we've got here and the opportunity that those guys have." Smith said Australia would not confirm its XI to face England until the toss. "We're pretty clear where we're sort of heading but I need to have a look at the surface when we get an opportunity," he said. Following the England clash, Australia plays South Africa in Rawalpindi on Tuesday AEDT, before meeting Afghanistan in Lahore later in the week.