The Blues have landed several ex-warriors when the Pontypridd and Bridgend region disbanded at the end of last season.
And McCall thinks the influx of quality will help the Welsh capital club no ends when they travel to Ravenhill for the Pool Six opener in October.
"The difficulty of the pool isn't a shock to us given our seeding as the third Irish side," said McCall, who will also face French champions Stade, English giants Gloucester as well as the Blues. "We know a lot about the Blues from the Celtic League and they improved great deal last season.
"And now they're going to be even stronger with the influx of players from the Celtic Warriors. But we'll still be looking forward to the opener against them."
Despite the quality of the group opposition, McCall revealed the target for the 1999 winners was the knock-out stages at least.
"It's obviously going to be a tough trip to Kingsholm and Gloucester," he said. "They've proved themselves to be one of the top teams in England over the last few years - and we are getting sued to playing Stade Francais.
'But I am very excited about the squad of players I've got to work with and Ulster went through last season unbeaten at home in the Heineken Cup and Celtic League, so I don't think anyone will be relishing a trip to Ravenhill.
'The number one priority for the season will be to make the last eight of the Heineken Cup - that's something we've failed to do since we won the title back in 1999. The standard has risen every season since then, but we feel we can be very competitive and we're looking forward to starting at home against the Blues.'