Seferovic: Switzerland were the better side
Switzerland were punished for not turning their dominance into goals, as Group E rivals Slovenia emerged 1-0 winners courtesy of Milivoje Novakovic's 79th-minute penalty in Maribor.
The Swiss - 10th in the FIFA rankings - had countless opportunities to get on the scoresheet but they were thwarted by Slovenia goalkeeper Samir Handanovic throughout.
Seferovic was one of the players denied by Handanovic and the 22-year-old forward was disappointed as Switzerland were left searching for their first win in qualifying after last month's 2-0 loss to England.
"We wanted the three points and honestly we were the better team," Handanovic said.
"But Slovenia scored and we're going home empty-handed. We have had lots of chances but we didn't make the most of them. That was our biggest mistake.
"In the end we conceded a goal and that was that. We are not happy, but we have to move forward."
Switzerland coach Vladimir Petkovic was also left ruing his side's profligacy.
"The result does not reflect the real situation on the pitch, unfortunately," said Petkovic.
"I am actually pleased with my players' showing. But if you don't score, you can't win. We missed many opportunities, hit the woodwork.
"Passes need to be more precise, I told that to the players many times, but ... everyone must take their share of responsibility. The result is negative but we don't have much time to recover."
Petkovic added: "We still have a lot of matches in this qualifying campaign and have every chance of coming back. It will not be easy, of course. I believe that this defeat will not have major consequences."
Switzerland take on minnows San Marino on Tuesday.