Sarries made it seven league victories in a row as they beat the strugglers 23-18 at Kingston Park.
McCall's side are now expected to finish the campaign at the top of the table after maintaining their seven-point lead over Northampton Saints.
"It was a tough game and we expected a tough game," McCall told the Aviva Premiership's official website. "After last week we took the opportunity to leave a few players at home this weekend.
"It was our 18th win in 20 games in the Premiership, which is pretty good going. We've got to manage our resources as cleverly as we can."
Saracens return to action on Saturday when they face Clermont Auvergne at Twickenham Stadium in the Heineken Cup semi-finals.