Cahill capped a remarkable few days by getting his first goal of the season in the 2-0 victory against Everton at the Reebok Stadium.
The defender went into the match on a high after helping England defeat Denmark in a friendly in Copenhagen.
Coyle said: "It has been a terrific week for Gary. I have had numerous chats with him and Gary should be weighing in with five to 10 goals a season. He did that last season.
"He has been frustrated seeing shots hitting the woodwork and goalkeepers making great saves.
"Coming in on the back of representing his country, particularly England, one of the major forces in world football, it was an accomplished performance by him."
Source: PA
Source: PA