Robin van Persie lauded Feyenoord's fighting spirit as they produced a stunning performance to thrash fierce rivals Ajax 6-2 in Sunday's Klassieker.

Having played a key part in Feyenoord's first two goals, Van Persie put the contest beyond Ajax with a double before Tonny Vilhena and Yassin Ayoub wrapped up the win in style.

It was far from plain sailing for Giovanni van Bronckhorst's side, who fell behind early on before rallying to go 2-1 ahead, only for Hakim Ziyech to restore parity 33 minutes into a frantic encounter at De Kuip.

Van Persie, though, insisted that Feyenoord's belief never wavered as they went on to end a three-match winless run and score six goals against Ajax for the first time since November 1964.

"A bizarre contest," Van Persie, who urged more consistency from his team-mates, told Fox Sports.

"This match had everything. Goals, good football, passion, fight. I am proud of how we always came back.

"Everyone fought for it. Our spirit was the deciding factor.

"When it was at 3-2, I looked around me and I thought 'this is very beautiful'. That passion and the belief that we would win, I had to absorb that.

"I believe in these players. They can play so very well. It should only be more frequent and more constant, that is the aim."

Lasse Schone's dipping free-kick gave Ajax the lead inside eight minutes, but a pair of close-range finishes from Jens Toornstra and Steven Berghuis had Feyenoord ahead by the half-hour.

Parity was soon restored when Ziyech hammered home, but Van Persie struck either side of half-time to put Feyenoord in control.

The defeat leaves Ajax five points behind Eredivisie leaders PSV, and coach Erik ten Hag claimed his side cannot currently contemplate the title race unless their defence improves.

"I am very grumpy," he said. "I do not even want to think about the title race for the time being. We first have to turn this around.

"We are not disciplined and not consistent enough. We started well, put Feyenoord under very good pressure, came 0-1 and therefore almost 0-2. 

"We have to realise what has made us great. We have shown good things to the ball, but football is more than just ball possession. We were teased today."