David Jeffrey is expecting a close battle for the Premiership title after seeing Linfield's lead chopped from six points to four on Tuesday night.
The Blues, champions for five of the last six seasons, lost 1-0 at Coleraine while Portadown moved into second by coming from behind to win at Ballymena.
Linfield's next game is at home to League Cup winners Crusaders.
"It will be tight - there is a long way to go. Crusaders are buoyant, so Saturday will be tough," said Jeffrey.
"We would have liked a point at Coleraine. We dominated the game but, for all the possession, you have to be honest and say we did not work their keeper enough."
Jeffrey refused to be drawn when asked about his apparent frustration with some refereeing decisions.
"In this day and age, you cannot speak to referees and you cannot speak about them. So, I will let my silence do the talking," the Linfield manager added.
Coleraine manager Oran Kearney was thrilled with how his players picked themselves up after their disappointing showing against Crusaders in the League Cup final.
"Experiences like Saturday can crumble players, can finish their seasons, and we were adamant we would not let that happen," he said.
"We owed ourselves a performance as much as anything else, and, what a response. Hopefully we are back to the way we can play."