"It is not all doom and gloom. We have not lost yet, we will take that as a positive," defender Williams told British media.
"We feel we can beat any side, so while it is still a close group, if we have to win all of our games, we are confident enough we can do that," the Everton centre back added.
"And the more it goes on, they turn into must-wins. It is frustrating to take the lead again and not win and keep a clean sheet.
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"But it is not like the last one (against Georgia) where the second half was bad and we didn't do what we were supposed to do. I feel like we still played well, but in the end you see how close football can be."
Wales travel to Dublin to face group leaders Ireland (10 points) in March and are on the road again in June when they take on Serbia.
Only the group winners in European qualifying are guaranteed an automatic berth at the 2018 World Cup in Russia.
(Reporting by Shravanth Vijayakumar in Bengaluru; Editing by John O'Brien)
