After describing his side's performance against Spakenburg in midweek as "not good", AZ Alkmaar boss Ronald Koeman will hope for better when they return to Eredivisie action on Saturday.

Koeman was unimpressed by AZ's attempts to see off the amateur side in the KNVB Beker, the defending Dutch champions requiring extra time to progress to the quarter-finals.

But at least they managed to avoid defeat with Koeman quick to point out they were not the first side to struggle against unheralded opponents in cup action.

"It happens everywhere in cup football," Koeman told De Telegraaf newspaper.

"I saw the Real Madrid result the other night (they lost 4-0 to third-tier side Alcorcon) and wonder how it happens.

"But I never felt we would lose. We had enough chances and gave Spakenburg more problems as the game went on.

"But let me be clear, this was not good."

AZ have also underperformed in the league recently with just one win in the last six games. And they will not find it any easier at the weekend as they go to an FC Groningen side on a high from a 5-1 thrashing of Vitesse Arnhem in midweek.

Although Groningen were impressive, Vitesse were woeful and will have to improve markedly if they are to get anything from Saturday's trip to second-placed PSV Eindhoven.

"That defeat hurt a lot," said Vitesse coach Theo Bos.

"We started poorly and got worse. There was no conviction, no experience, no fight, we were nervous, it was awful. I felt ashamed."

Bos, however, ruled out following the example of NEC Nijmegen boss Dwight Lodeweges and resigning.

"I love this club. I will do everything to turn the tide," he added. "But the performance of the team was unacceptable. This will cost them money."

PSV won 2-0 at Roda JC on Wednesday night to maintain their unbeaten run in all competitions this season.

NEC will look to end a difficult week on a high with victory at Sparta Rotterdam.

Lodeweges quit on Tuesday after doubting his ability to arrest the club's recent slump.

Caretaker bosses Wim Rip and Wilfried Brookhuis led the side to an extra-time win over Excelsior in midweek but speculation continues to link Co Adriaanse with the vacancy.

Ajax host Feyenoord on Sunday in a clash between the third- and fourth-placed teams in the Eredivisie.

Before that, though, Ajax meet FC Dordrecht in the cup with coach Martin Jol insisting he won't be protecting players for the weekend clash.

"No, I won't be resting anyone," said Jol, who should have record signing Miralem Sulejmani back from injury for the meeting with the Rotterdammers although Ismail Aissati is battling to overcome a thigh injury.

Leaders FC Twente will look to maintain their seamless progress this season when they go to Roda.

The Enschede-based club are two points clear of PSV, hammered Groningen 4-0 last weekend and followed that up with a 3-0 defeat of Capelle in the KNVB Beker in midweek.

In addition, coach Steve McClaren agreed a contract extension on Tuesday which ties him to Twente until the end of the 2011 season.

If all is going well for McClaren and his men, the same cannot be said for Heerenveen, who host ADO Den Haag this Saturday.

Jan De Jonge took over as coach from the sacked Trond Sollied at the start of September but the change has failed to improve results with the club languishing towards the foot of the table.

Goalkeeper Brian Vandenbussche admits it is an unusual situation for him after a largely successful spell with the club.

The Belgian told Voetbal International: "I have played here for six seasons and this is the first time I have experienced this kind of situation.

"The past five seasons were superb with top players. This, of course, is not fun but the atmosphere is still good."

De Jonge could be boosted by the availability of Mika Vayrynen against ADO.

The Finland midfielder returned after a long absence for the 4-2 cup win over RBC Roosendaal last night and is hoping he will be fit for the weekend.

"Heerenveen needs me, but right now we desperately need every player," he said.

"I'm back, but obviously not immediately at my old level.

"If the knee does not suffer a negative reaction today, I can play again Saturday."

Heerenveen are only being kept off the bottom by RKC Waalwijk, who have mustered just three points from their 11 games.

RKC play host to Willem II this weekend while two upwardly mobile clubs in Heracles and FC Utrecht meet in Almelo.

The weekend action kicks-off on Friday night when VVV-Venlo meet NAC Breda.