Australia sparked their World Cup campaign into life thanks to a 1-0 win over Tunisia, secured by Mitchell Duke's excellent first-half header
The Socceroos, who , went into the game knowing another defeat would end their World Cup with a game to spare
Graham Arnold's side started like a team that knew they had to bounce back and forced Tunisia to spend much of the opening exchanges inside their own half
Australia's pressure told in the 23rd minute, when Craig Goodwin's left-wing cross took a deflection before finding Duke, who readjusted superbly to guide a glancing header past the despairing Aymen Dahmen and inside the far post
Tunisia improved after the break but struggled to break down a resolute Australia, who now lie second in Group D with three points ahead of France's clash with Denmark on Saturday afternoon, while Tunisia are bottom with just one point and zero goals
Australia's win over Tunisia was just their third at a World Cup - and their first since beating Serbia in 2010 - but came at the perfect moment, keeping alive their hopes of reaching the last 16 for just the second time
Tunisia had been impressive in their  but struggled to contain Australia in the first 30 minutes, with the African side repeatedly being exposed down their right flank
Australia eventually took advantage, with Duke playing a deft lay-off to Riley McGree before making his way into the box, where he met Goodwin's cross from the left
Tunisia belatedly began to exert some pressure on Australia and should have levelled when smart hold-up play from Issam Jebali helped to set up Mohamed Drager, but his close-range shot was blocked by a brilliant sliding tackle from Harry Souttar
More good work from Jebali then presented Youssef Msakni with a glorious chance in the centre of the Australia area, but he could only bend his first-time effort wide
Tunisia moved away from their three-man defence in the second half as they chased a leveller, but it was Australia who should have scored the game's second goal, with Matthew Leckie just failing to stretch enough to turn in Jamie Maclaren's left-wing cross
Despite their tactical switch, Tunisia struggled to create any clear openings after half-time, with Wahbi Khazri's stabbed effort - comfortably saved by Mathew Ryan - their best chance as the game moved towards stoppage time
Thanks to some stout defending by the outstanding Souttar and a midfield marshalled by the intelligent Aaron Mooy, Australia kept Tunisia at arm's length to earn the three points and move within one win of the last 16
Australia's win means they are second in Group D, behind France on goal difference, while Tunisia are bottom
 However, France could move three points clear with a win over Denmark on Saturday afternoon
 A Denmark win would see Australia move back to third
Australia will qualify for the last 16 if they beat Denmark on Wednesday
 Tunisia must beat reigning champions France on the same day to have any hope of progressing to the last 16 of a World Cup for the first time
Harry Souttar had played just one full match this season before heading to the World Cup after recovering just in time from an ACL injury, but he showed no signs of rust as he led Australia to a vital win
The Stoke centre-back recorded three blocks, six clearances and seven ball recoveries on his way to completing the full game, including his goal-saving block in the first half and a rugged sliding challenge to halt a Tunisia counter-attack in the second period
Along with centre-back partner Kye Rowles, Souttar's display helped earn Australia their first clean sheet at a World Cup in 48 years
Australia boss Graham Arnold was in bullish mood after their victory, saying: "When the doubters hate us, bring it on
""I'm just hugely proud of the boys," he added
 "They showed that great, fighting Aussie spirit
 We were in their faces all the time and I expect we made the nation very proud
"The other night, we played against the current world champions and the boys had the same effort level
 The effort levels were incredible
"The match was played during prime time in Australia and when asked about the support back home, Arnold said: "I could feel all my mates cheering and drinking those beers!"Tunisia coach Jalel Kadri bemoaned the passive nature of his side's performance, saying: "It was a very tough match between two very tough teams
"I think today we should have played to win
 We still have one match to play and we will play with our hearts out
"
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