Steve Smith has ridden his luck on the way to posting a valuable half-century as Australia reached 264 from 49.3 overs in their Champions Trophy semi-final blockbuster against India in Dubai.

Australia's decision to punt on Cooper Connolly as a replacement for injured opener Matt Short backfired, with the 21-year-old looking all at sea on the way to a nine-ball duck.

But Smith's 73 off 96 balls and Alex Carey's 61 off 57 helped lift Australia to a respectable total on a dry-looking Dubai pitch.

At 4-198 in the 37th over, Australia were on track for a score in excess of 300.

But the loss of Smith and Glenn Maxwell (7) in quick succession halted Australia's momentum.

The in-form Carey took over with a quick-fire knock that featured eight fours and a six.

But when he was run out via a direct hit from Shreyas Iyer at the end of the 47th over it meant Australia were unable to cash in at the death.

Paceman Mohammed Shami led the way for India with 3-48, while spinners Varun Chakaravarthy (2-49) and Ravindra Jadeja (2-40) provided good support.

Smith received a huge slice of luck on 23 when he edged the ball onto his pads and it rolled to hit his off-stump - only for the bails to stay on.

Then when Smith was on 36, Shami dropped a tough one-handed return catch.

Smith made the most of the double reprieve, registering four fours and one six in his measured knock.

But his time in the middle was finally brought to an end when he missed a full toss from Shami, with Smith berating himself as he walked off the field.

Smith wasn't the only player to receive a lucky break during his innings.

Dangerman Travis Head was yet to score when Shami dropped a one-handed chance off his own bowling - much like the Smith missed chance that happened later in the innings.

Head made 137 off 120 balls in Australia's win over India in the final of the 2023 ODI World Cup.

But this time the damage was limited to 39 off 33 balls, with Head skying a catch to Shubman Gill on the first ball he faced from Chakaravarthy.

Smith's exit in the 37th over sparked a collapse of 6-66 as Australia's hopes of posting a score in excess of 300 faded.

Their final total would have been even lower if not for the efforts of Carey, who batted well with the tail before making the ill-fated decision to come back for a second run in the 47th over.

Besides Connolly replacing Short, Australia brought in spinner Tanveer Sangha for pacer Spencer Johnson.

The winner of the semi-final will take on either South Africa or New Zealand in Sunday's decider.