Scotland had needed a 94th-minute goal from Scott McTominay to earn a vital 3-2 triumph over Israel on Saturday and again left it late as Dykes found the net four minutes from time to steal a 1-0 win.
The result consolidates Scotland’s position in second-place in Group F, four points clear of third-placed Israel, and they can secure a playoff spot by beating Moldova next month.
In the same group, Denmark continued their perfect campaign to confirm top spot and become the third team, after Germany and hosts Qatar, to reach next year’s tournament.
The Euro 2020 semi-finalists beat Austria 1-0 thanks to Joakim Maehle’s goal, which extended their qualifying record to eight wins from eight without conceding a goal.
Cristiano Ronaldo took his international goal tally to 115 with a hat-trick as Portugal beat Luxembourg 5-0 to keep the initiative in Group A.
They currently trail leaders Serbia by a point but having played a game fewer, with the pair set to meet on the final day of qualifying in what will be a winner-takes-all affair, though Portugal will be top by then should they avoid defeat against the Republic of Ireland next month.
Sweden, meanwhile, went top of Group B with victory over Greece and have a two-point cushion over second-placed Spain having played the same number of games, though Luis Enrique’s men still have their fate in their own hands as the Swedes must go to Seville next month.
Italy are another powerhouse not having it all their own way after Switzerland thumped Lithuania 4-0 to move level on points with the European Champions at the top of Group C.