Ronald Koeman believes the Netherlands must improve on the "sloppy" aspects of their game despite Thursday's 3-1 win over Tunisia securing top spot in their World Cup group.

The Netherlands edged out Japan and Sweden to clinch first place in Group F as Brian Brobbey and Jan Paul van Hecke got on the scoresheet following an early own goal from Ellyes Skhiri.

The Oranje found themselves 2-0 up within six minutes and 24 seconds, the fastest such start by any team in a World Cup match since 2002, when Poland led the United States 2-0 after four minutes and 21 seconds.

However, Tunisia then battled back into the contest and halved the arrears through Hazem Mastouri's header in the second half, though Van Hecke's glancing effort restored the Netherlands' two-goal cushion eight minutes later.

The Netherlands had a 71.7% possession share against Tunisia, their highest on record (since 1966) in a World Cup match, while it is just the second time they have scored 10 goals in the group stage at the tournament, after 2014. 

However, with a tricky last-32 tie against Morocco now awaiting his team, Koeman believes they cannot afford to offer their opponents any encouragement.

"We hoped for a good start and that happened. It was 2-0 pretty quickly. After that, we continued well, but there were moments in the transition when they became dangerous," Koeman told NOS. 

"The phase before half-time and the phase after the break were not good. You could see that there was not much going on.

"You want to play a match as a whole well, not with those sloppy moments in possession. 

"Because if you play better teams... We have seen that against Japan, or even Sweden, that can cost you your head."

The Netherlands will face Morocco – who finished as Group C runners-up behind Brazil – in Monterrey on Monday, which could mean playing in searing temperatures after they were spared the worst of the summer conditions throughout the group stage. 

"We haven't been hot in Kansas City, we played indoors twice [in Houston] and today we were fortunately able to play with nice temperatures," Koeman added.

"If it gets hot there, then we just have to accept that."

Tunisia, meanwhile, exit the tournament with zero points and 12 goals conceded – the most by any team in the World Cup's group stage since North Korea in 2010 (also 12) and the most outright by any team at a single edition since Brazil in 2014 (14 goals conceded in seven games, including a 7-1 loss to Germany).

Herve Renard was hired as their coach one game into the tournament, with Sabri Lamouchi sacked after a 5-1 loss to Sweden, but he has no regrets about taking the job. 

"We were not at the level for this World Cup. This is clear. There is no discussion," he said. "The federation called me for a very short mission.

"We agreed on that deal and rather than stay on my couch, watching this amazing event from very far away, I thought; 'I've got nothing to lose.'"