Top athletes including Britain's 10,000m champion Mo Farah and US hurdler Aries Merritt have expressed disappointment over the turnout at the vast 84,745-capacity Luzhniki stadium, which hosted the boycott-stained 1980 Moscow Olympics.
Morning sessions for qualifying events have taken place in an almost empty stadium while there were rows of seats spare even to see Usain Bolt's victory in the blue riband men's 100m on Sunday night.
Tatyana Lebedeva, a former Olympic women's long jump champion and now vice-president of the Russian Athletics Federation, admitted there were teething problems but begged for patience as Russia was on a steep learning curve.
"Yes the stands are absolutely not full. Yes, tickets are being given away for free. And in the end the organisers are not getting by without mistakes," she wrote in the Sovietsky Sport daily.
"For example, the decathletes have a tradition of doing a lap of honour (after their event Sunday) but we asked the athletes to get off the track. The tradition was broken. But believe me, this mistake will not happen again. We are learning and learning with pleasure."
Athletics is by no means a wildly popular sport in the ice hockey- and football-mad country -- and interest can be alarmingly dependent on the success of Russian sportsmen and women.