Hearts have been knocked out of the Europa League, lost their opening league match to Celtic and were knocked out of the Betfred Cup by St Johnstone.
This contrasts with strong performances at the start of the last two seasons.
"The actual performances in the first two competitive games in Scotland have been far better than the previous two seasons," Neilson explained.
"Although we picked up more points in the first two seasons, in my opinion and the players' opinion as well, the performances have been really good.
"We rode our luck the first two years but performance-wise it's been far superior. It's just small detail that is costing us at the moment."
Neilson says he knows there are dissenting voices in the crowd after the poor results but insists it comes with the job.
"That's football," he said. "It's important we stay consistent and we keep progressing and stay positive, even after difficult results.
"It's about performance and about progressing this team, progressing the young players and we are doing that so we have just got to accept that sometimes we have little periods when we don't get the result we are looking for.
"It's very early days of the season for us. The players have done exceptionally well for us for the past two seasons and will do exceptionally well this season as well."
Neilson takes his team to face Aberdeen on Saturday and is confident the team are good enough to win at Pittodrie.
"It's a tough game and once again it will come down to the small details," he said.
"We need to make sure we don't make silly errors like we have in the last two games and I'm sure the performance will be good enough to take the three points."
Head coach Robbie Neilson claims Hearts are playing better than they did at the start of the last few seasons.