Qotbi admitted that Iran had a tough second half against North Korea, saying it would be difficult for any team to win in Pyongyang.
"The match was very important for both teams so there was clearly a lot of stress for both the North Korean and the Iran team," Qotbi told reporters after the match, which ended in a goalless draw.
"The first half, I think, the Iran team was fantastic, organized. We controlled the match, gave no opportunities and I thought that we had three or four clear chances to score. And I think in international football you have to at least finish one of those chances."
The draw against North Korea means Iran will have to beat the UAE and South Korea in its two remaining matches to secure at least the third place in Group B of World Qualifiers and sweep into the play-off round.
"It's now an uphill battle. We must win [in the match against the UAE in Tehran] so we can at least give ourselves a chance in Seoul to go the World Cup," Qotbi said.
South Korea beat the UAE 2-0 on Saturday to top the group with 14 points and qualify for the World Cup.
North Korea, which is second with 11 points out of seven matches, will play its last game against Saudi Arabia, which is third on 10 points from six matches. Iran lies in the fourth place with seven points from six matches.
Asian World Cup qualifying results
Group A
Qatar 0 Australia 0 (Australia qualifies)
Uzbekistan 0 Japan 1 (Japan qualifies)
Group B
North Korea 0 Iran 0
United Arab Emirates 0 South Korea 2 (South Korea qualifies)