Saracens director of rugby believes Exeter were the hungrier team and deserved their 14-12 victory at Sandy Park.
The Men in Black's coach was disappointed with his team's performance and said ill-discipline let them down.
"Exeter were much better than us today, they looked the hungrier side," McCall said.
"Our fundamentals let us down – we gave a lot of penalties away and if you spend 60 mins of the game with 14 men it's always going to be difficult.
"Our yellow cards and penalty count just wasn't good enough."