After taking over from Peter Reid towards the end of the last year, Robson was tasked with the goal of securing a place at Asia's showpiece tournament. Thailand needed three points in Iran if they were to snatch a place in Doha next year but rarely looked like scoring before Osasuna's Javed Nekounam settled the encounter with a 90th-minute strike.
"It is very upsetting not to be in the finals of the tournament," said Robson. "The team has had many problems since I arrived here, I did my best to resolve these problems but in the end I could not find a solution to the problems of my attack.
"Iran are a very strong team, they were both technically and physically better than us and this superiority accounted for the victory they gained. I wish them all the best in the tournament in Qatar. I am hopeful Thailand's young talents can some day resolve their problems with regards to scoring. We really had big problems due to poor finishing. "
The game was of little significance for Iran with their place at the Asian Cup having already been assured but coach Afshin Ghotbi was delighted the battling qualities of his players were on display up to the final whistle.
"We had a tough job against Thailand today, they were mainly thinking about defending and breaking on counter-attacks," he said. "They finally got the reward for their perseverance by scoring the winner in the stoppage time."
Jordan will join group winners Iran at the Asian Cup finals after they beat Singapore 2-1 to claim second place. Odai Al Saify put the hosts ahead after nine minutes and though Singapore levelled four minutes after the break through Noh Alam Shah, Jordan secured the win when Anas Bani Yaseen struck just after the hour mark.
"This win is a big achievement for our national team as we were so far behind in the qualifiers before returning to winning ways and achieved qualification to the finals, although it came in the last match," said Jordan coach Adnan Hamad.