Icardi found the target in each half thanks to two assists from French international Kylian Mbappe.
Real Sociedad ruined Elche's return to the top flight as they won 3-0 in Elche's Martin Valero stadium with second half goals from Portu, Adnan Januzaj and Roberto Lopez.
Thepchaiya Un-Nooh from Thailand won the other group on Saturday.
Zhejiang's Wang Shun clinched gold in the men's 200m individual medley in 1:56.83, leading silver medalist Deng Ziqi from Guangdong by around five seconds. Liu Zongyu from Shandong took the bronze.
However, there was also good news.
Defending champions Paris Saint-Germain will travel to play Stade Reims on Sunday, with both Neymar and Kylian Mbappe available for Thomas Tuchel's side for the first time this season. Enditem
Although the club offered no further explanation, merely stating the injury was "pending evolution," it means that Hazard (who didn't play in Madrid's first two matches of the new season) drops out of the squad to face Valladolid in the Alfredo Di Stefano this Wednesday night and makes him a major doubt for the weekend's away trip to play Levante.
Porto currently have three Brazilians in their first-team squad: defender Alex Telles, midfielder Otavio and forward Evanilson. Enditem
"The plan was to put Neymar close to Mbappe. We chose an offensive structure. We tried something and I have a lot of confidence in my team," Tuchel said after the match.
Ibrahima Niane scored in the 71st minute to give Metz the lead, but midfielder Morgan Sanson's goal in stoppage time saved the game for the hosts.
"I think the time will be fast, London is a big race and all the participants are in good shape and able to run faster times," Kipchoge, who holds the official world marathon record of 2:01:39, told Xinhua on Sunday.