The World Anti-Doping Agency (WADA) has said it has "successfully retrieved" data from the Moscow laboratory at the heart of Russia's state-sponsored doping scandal which involved more than 1,000 athletes and 30 sports.
WADA had demanded the data be handed over to complete its investigation into the 2011-2015 scandal which saw Russia's athletics team barred from the 2016 Rio Olympics and exiled from the 2018 Winter Olympics.
"This is a major breakthrough for clean sport," said WADA President Craig Reedie.
In September, WADA conditionally lifted a ban on the Russian Anti-Doping Agency (RUSADA), paving the way for its reinstatement.
One of the conditions was access being granted to the data by the end of 2018.
But when a WADA team arrived last month, Russian authorities raised issues with the certification of their equipment under Russian law and a 31 December deadline was missed.
"It shows we are continuing to make real progress that simply would not have happened without the 20 September decision," insisted Mr Reedie.
"The first phase of the three-phase process outlined by that decision is now complete. The long impasse around access to the former Moscow Laboratory has been broken and that is significantly good news."
Mr Reedie said that WADA will now attempt to authenticate and review the data to ensure it is complete and "that it has not been compromised".
"Once the data have been authenticated, we will be in a position to proceed to the third phase and support the various sports and other anti-doping organisations concerned to build strong cases against athletes who doped and, as part of that, ensure that certain samples that are still stored in the Moscow Laboratory are re-analysed in an accredited laboratory no later than 30 June, 2019."
The Independent Compliance Review has now submitted a recommendation to be considered by WADA's executive committee on 22 January.
WADA was strongly criticised over its decision to lift Russia's suspension in September before obtaining access to the anti-doping laboratory in Moscow.
Outspoken US Anti-Doping Agency chief Travis Tygart had described Moscow missing the 31 December deadline as "a total joke".
"In September, WADA secretly moved the goal posts and reinstated Russia against the wishes of athletes, governments and the public," Mr Tygart said.
"The situation is a total joke and an embarrassment for WADA and the global anti-doping system."
However, in his New Year message, International Olympic Committee president Thomas Bach insisted Russia had been sufficiently punished.
"With its suspension from the Olympic Winter Games PyeongChang 2018, the Russian Olympic Committee has served its sanction," wrote Mr Bach.
RUSADA was initially suspended by WADA in 2016 after an independent report by Professor Richard McLaren found widespread evidence of state‑sponsored doping in the country.
Dick Pound, who was WADA's inaugural president from 1999 to 2007, told AFP recently that once access to the lab had been granted the authenticity of the samples "was the big question".
"But until you get the data you can't examine it in a forensic manner to see if it's complete and whether it's been tampered with," said Mr Pound.
"So that's probably going to take a month or two months because there are 9,000 samples that we need to study."