Substitute Javad Kazemian struck in the 77th minute to give Iran a come-from-behind 2-1 victory over Uzbekistan in their Asian Cup Group C match on Wednesday.
The 26-year-old rescued a largely disappointing Iran side, who struggled to find their rhythm against the combative Central Asians.
Uzbekistan, with main striker Maksim Shatskikh suspended, took the lead on 15 minutes through an own goal by Iran defender Rahman Rezaei.
Iran levelled in the 55th minute when Seyed Jalal Hosseini scored from a corner before Kazemian emerged as the hero.
Iran coach Amir Ghalenoei said his team's superior fitness was the key.
"When I took over this team, my first priority was to improve fitness levels," he told reporters.
"After 60 minutes, that was when we really started to dominate Uzbekistan because our players were fit and able to compete better.
"Uzbekistan prepared well and it was difficult getting used to the heat in Kuala Lumpur but I am satisfied to have a win in our first game."
The victory put Iran in second place in Group C behind China, who beat hosts Malaysia 5-1 on Tuesday. The top two teams advance to the quarter-finals.
With both teams playing cautiously, Uzbekistan took an unlikely lead. Captain Server Djeparov sent a high ball forward trying to find striker Ulugbek Bakaev.
Rezaei, under pressure from Bakaev, tried to head back to goalkeeper Hassan Rodbarian but only succeed in finding the back of his own net.
Iran came out more determined in the second half and equalised after captain Mehdi Mahdavikia made his first foray upfield.
The skipper sent in a testing corner from the left and defender Hosseini rose high to head past Uzbek goalkeeper Pavel Bugalo.
Kazemian settled it for Iran when he received Andranik Teymourian's through ball on the edge of the box and drilled it past Bugalo.
Tempers frayed on the sidelines towards the end of the match with Ghalenoei sent to stands by Kuwaiti referee Saad Al Fadhli for apparently throwing a water bottle at the fourth official, though the coach said his anger was directed at one of his players.