LOS ANGELES – Doc Rivers often thinks about his father, a former Chicago police lieutenant who taught him life lessons that the Boston Celtics coach relies on to guide his team.

Grady Rivers preached patience, consistency and hard work. He juggled his schedule so he could watch his son’s games. He coached his kid’s baseball team and proudly watched Doc become a college star, NBA player and grow into a respected family man.

In November, Grady Rivers died following a brief illness.

Doc Rivers, once criticized for his coaching style, is now within grasp of a lifelong dream, one he shared with his dad. He’s one win away from winning an NBA title that eluded him during a 13-year playing career. Rivers is on the verge of bringing another championship to Boston, city of champions.

Rivers will go for it on Sunday – Father’s Day.

With his team holding a commanding 3-1 lead over the Los Angeles Lakers in the NBA Finals following a historic comeback in Game 4 on Thursday night, Rivers, whose team won only 24 games a year ago, was asked during a news conference to reflect on his father’s influence.

“I … can’t,” Rivers said, choking back tears.

He sat quietly for more than 30 seconds, unable to speak about his dad as a respectful silence fell over the Lakers’ practice facility.

“That’s just a tough one for me to talk about,” he said, fighting the emotion.

A reporter offered a lighter question about whether he might coach Sunday’s game with a cigar in his jacket pocket, a la legendary Celtics coach Red Auerbach.

“No,” Rivers said, laughing and thankful for a break. “I will not. Red is always on our mind, obviously, but I won’t do that. As far as we are concerned, we have to win a game, and the next game is our focus.”

Finally more composed, Rivers returned to thoughts about his late father.

“He’s just very important in my life,” Rivers said. “It’s still very difficult for me to talk about because I haven’t had a lot of time to reflect on it. It happened during the season unexpectedly. It’s very, very difficult. But I do think about it.

“I think about it a lot.”

The Celtics can with their 17th championship and first since 1986 with a win in Game 5 on Sunday. They put themselves in this position by overcoming a 24-point deficit in the first half on Thursday to beat the Lakers, who left the floor of the Staples Center in stunned disbelief.

Lakers coach Phil Jackson canceled practice Friday, giving his players a chance to rest up physically and psychologically. He brought his players in to watch video and did his best to convince them they can become the first team in finals history to overcome a 3-1 deficit.