GUANGZHOU, China (AFP) - Keigi Higashi's 45th-minute goal gave Japan a 1-0 win over Thailand and a spot in the Asian Games semi-finals on Friday where they were joined by fellow regional power South Korea.
The 20-year-old Higashi struck just before half-time, slotting the ball home from close range and past goalkeeper Samuel Cunningham.
Japan, top scorers in the tournament with 14 goals, will now face four-time champions Iran, who defeated Oman 1-0.
"Thailand controlled the ball well, but we controlled the match," said Japan coach Takashi Sekizuka.
"It was a tough match and we were lucky to score in the first half and we were able to defend in the second."
Thailand, coached by former England skipper Bryan Robson, created most of the pressure in the quarter-final clash but were unable to find the finishing touch.
"It's unfortunate. We were the better team over the 90 minutes," said former Manchester United captain Robson.
"We passed the ball well and got into good positions, but couldn't convert any of our chances."
South Korea were forced to extra-time before seeing off 10-man Uzbekistan 3-1 in their quarter-final and will now tackle the United Arab Emirates for a place in the gold medal match.
Hong Jeong-Ho put South Korea in front after just two minutes, but Sherzodbek Karimov pounced on a mistake by left-back Shin Kwang-Hoon in the 71st minute to equalise.
Uzbekistan played the last 30 minutes of the game with 10 men after star striker Ivan Nagaev was sent-off.
Monaco's Park Chu-Young, with his third goal of the tournament, restored his team's advantage in the second minute of extra-time with a smart twist and drive which goalkeeper Timur Juraev allowed to squeeze beneath his body.
Kim Bo-Kyung added the third in the 101st minute for an attack-minded South Korean team who peppered the target with 22 shots.
South Korea coach Hong Myung-Bo praised the influence of Park Chu-Young.
"He is an experienced player and leads by example. With him in our team we know what we are capable of," he said.
The UAE defeated North Korea 9-8 in a penalty shootout after the two sides had battled to a 0-0 draw after extra-time.
Ri Chol-Myong had his penalty kick saved by Ali Housani in the UAE goal before Mohamed Al Shehhi tucked away his spotkick to send the Gulf side into the semi-finals.
|De Gea coy over Real links|
|Former Brazil star Carlos handed Delhi reins|
|Ciftci will not push through Celtic switch – agent|
|In-demand Mitrovic considering Roma offer|
|Lehmann calls on Cech to ´get over´ Chelsea|
|Marlos double sinks Monaco|
|Mauritius 0 South Africa 2 (agg 0-5): Bafana set up Angola qualifier|
|Keane relishing Gerrard arrival|
|Palace confirm Cabaye interest|
|Hamburg bring in Spahic after head-butt ban|
|Blatter hits out at France and Germany over World Cup votes|
|Sanchez: World Cup exit spurred Chile to Copa glory|
|Jojic makes Cologne switch, Santana move falls through|
|Carrillo keen to get going at Monaco|
|Micronesia thrashed 38-0 as Fiji triumph in Olympic qualifier|
|Schalke stunned by ´machine´ Caicara|
|MLS Review: Keane shines at Gerrard´s Galaxy unveiling|
|Counter-attacking the key for Japan|
|Jimenez happy at Atletico|
|Gerrard predicts ´successful future´ with Galaxy|
|Iniesta can´t see Real selling Ramos|
|Keshi sacked as Nigeria coach|
|Three finals, three defeats for Messi, Mascherano|
|Nani close to Fenerbahce move|
|Sampaoli revels in ´unbelievable joy´|
|Bravo: Copa victory a dream|
|Martino: Argentina should have won|
|Chile 0 Argentina 0 (4-1 on penalties): Hosts end trophy drought|
|Germany 0 England 1 (after extra time): England make World Cup history|
|Kenya 0 Ethiopia 0 (agg 0-2): Hosts sent out of CHAN qualifiers after second penalty miss|
|Dortmund put 17 past Olympians, Bremen hand out thrashing|
|Dinamo Zagreb confirm arrests of coach and club president|
|I didn´t know who Wimbledon guest Klopp was - Brown|
|LeBron James backs Liverpool captain Henderson for FIFA 16 cover.|
|Ramos: I am not negotiating with anyone|
|Valencia complete Mina swoop|
|United States v Japan: US seek final redemption|
|Hanousek consigns Celtic to defeat|
|Roma confirm Dzeko interest|
|Arsenal forward Podolski completes Galatasaray switch|
|Warm Dortmund welcome delights Tuchel|
|Silva vows to fight for Madrid place|
|Mancini hints at Shaqiri and Santon departures|
|Bojan raring to go after return from injury|
|Babel backs Firmino to shine at Liverpool|
|Falcao must wait to impress, warns Chelsea favourite|
|Bartomeu: Deal in place for Turan|
|Parejo re-signs with Valencia|
|MLS Review: Sounders return to winning ways|
|Klinsmann unhappy with USA performance|
|High hopes for Paraguay - Diaz|
|Gareca: More to come from Peru|
|Gerrard had European offers|
|Argentina out to spoil Chile´s party - Martino|
|Sampaoli: Chile won´t change style|
|Di Maria will come good at United - Rojo|
|Peru 2 Paraguay 0: Gareca´s men finish third at Copa|
|United States 4 Guatemala 0: Klinsmann´s men win comfortably|
|´I’d prefer no-one to know my name´ - Bassett|
|Matthews completes Sunderland move|
|Podolski set for Galatasaray medical|
|Gundogan inspires Dortmund victory|
|Inter confirm Montoya capture|
|Murillo joins Inter, as Kuzmanovic and Obi depart|
|Falcao signing not a risk, says former Chelsea star|
|Deeney agrees new Watford deal|
|Confidence and service the key to Falcao success at Chelsea|
|No bids for ´Chelsea target´ Baba, claim Augsburg|
|Derby swoop for Ince|
|Fiorentina consider legal action over Salah ´no-show´|
|Chelsea the team to beat in the Premier League, says Neville|
|Storari exits Juve for Cagliari|
|UEFA removes FFP restrictions on Man City and PSG|
|West Brom hope for new owners within the month|
|Chelsea agree loan deal for Falcao|
|Kuyt eyes trophies on Feyenoord return|
|Chile v Argentina: History beckons ahead of Copa America final|
|Wallace extends Monaco loan|
|Mihajlovic wants to instill fear factor at Milan|
|Mignolet improving at Liverpool - Grobbelaar|
|Mumbai City name Anelka player-manager|
|Olivia the parrot predicts Japan to win Women´s World Cup|
|Lusitans coach blasts Bilic´s ´lack of respect´|
|Sakho eyes more Europa League wins|
|Gareca wants Peru to keep building|
|Chile ´no chance´ if Argentina produce their best - Diaz|
|Ocampos joins Marseille permanently|
|Europa League Review: Cloud-nine Brondby ignite opening round|