Van Dijk captained the Netherlands to a 1-0 victory away at Latvia, with Davy Klaassen's goal after 19 minutes proving decisive.
Salah's Egypt won by the same scoreline when they hosted Libya in the CAF section of qualifying as Liverpool's No.11 played all 90 minutes of the contest.
Meanwhile, Williams delivered the assist for Aaron Ramsey's opener as Wales went on to draw 2-2 with the Czech Republic in Prague.