The city team have won only one of their last five English Premier League fixtures to slide to eighth position – the final play-off spot - in the standings.
And while Robson is not about to panic, he does accept that Phantoms cannot continue to allow leads to slip on a regular basis.
They have done it during their last three games and while they did eventually prevail after penalties against title-chasing Telford 11 days ago, there was no such happy ending in two outings last weekend (9October 8/9).
They were beaten 5-3 by Swindon, after early recovering from 2-0 down to lead 3-2 at the end of the second period, before allowing a four-goal lead to slip when going down 5-4 after penalties to Sheffield.
“We’re not worried,” said Robson. “We know what we are capable of doing when everyone clicks, and we also feel sure that will soon happen again.
“Dipping below the 50 per cent ratio for the first time this season was not ideal last weekend, but winning four of our first 10 games is not the worst start either.
“The league looks to be a lot stronger all-round this year and there have been plenty of surprise results already. Bracknell won at Guildford last weekend and we’ve probably had a couple of them ourselves.
“I’m convinced we will push on and be up there by the end of the season, but we’ve got to make sure we are mentally switched on for the full 60 minutes.
“We can’t continue to throw leads away. We’ll learn from it, adapt our game and try to put things right.”
Phantoms have a five-point cushion over the Bracknell side, who sit below them in the table.
Despite being eighth, the city men are only eight points off the top in a division led by Telford.