Ajax came into their match at Fortuna Sittard knowing they could ill afford to lose any further ground on PSV Eindhoven at the top of the Eredivisie.
Dusan Tadic saw his shot put out for a corner after the faintest of touches from Fortuna goalkeeper Alexei Koselev.
Fortuna's best moment of the first half came just before the break - Lisandro Semedo crossed, the ball was cleared into the path of Ahmed El Messaoudi, who fired in a low shot that was fended away by the boot of Ajax goalkeeper Andre Onana.
Ajax went in front four minutes after the restart - Tadic was involved in a 1-2 before feeding substitute Kasper Dolberg, who tucked the ball under the advancing Koselev.
At the other end, Lazaros Lamprou tested Onana from distance but the Ajax keeper saved well. And it wasn't long before the visitors had the comfort of a two-goal cushion.
Donny van de Beek headed the ball over the top of the Fortuna back line and and Hakim Ziyech timed his run perfectly before beating Koselev in the Fortuna goal to make it 2-0 in the 78th minute.
The home side didn't give up and Andrija Novakovich forced Onana into another save in stoppage time. However, no more goals, a clean sheet for Ajax - and more importantly a win that means they're now five points behind PSV.