The International Olympic Committee has confirmed Athens will be ready to host this summer's Games, which start in the Greek capital on 13 August.
"We had doubts about some of the venues and infrastructure, but I am very happy to report these have all disappeared," said IOC chief overseer Denis Oswald.
"No single project is at risk - we know everything will be delivered on time."
He said the inspectors' visit had been "positive" and praised the work on the installation of the stadium roof.
Oswald said that the Olympic movement and the Greek people would benefit from the Games returning to their spiritual home.
"The movement will profit a lot from having the Games in Greece - we return to our roots, so it will remind us to put the basic philosophy of the Olympic movement in first place," he said.
"It is evidence of the capacity of Greece to master such a huge task - this is a tremendous asset to the image and people of Greece."
Gianna Angelopoulus-Daskalaki, the leader of the Athens organising group, also paid tribute to the local workers.
She said they had managed to fit seven years' work into four years, and that this was a tribute to what the nation could do when they were "focused".
British Olympic Committee chairman Craig Readie warned that the physical construction was only part of the process, however.
"Having completed the venues, the Olympic overlays have got to go into it - all the technical work has to be done, and the move from a construction organisation into an operational organisation," he told BBC Five Live.
"Sometimes that takes a bit of doing as well."
One of the main stumbling blocks has been the installation of the elaborate roof structure for the main stadium.
The 18,000 tonne roof had been expected to be installed by the end of April, but work on putting it into place only began on 10 May.