LOS ANGELES (AP) — Doc Rivers suddenly fell silent, choked by emotion.

One of the NBA’s most loquacious coaches, he couldn’t find the right words to describe the feeling tearing him apart.

On Friday, Rivers trembled as he thought about his late father, a former Chicago police lieutenant who taught him life lessons — patience, consistency and hard work — that the Celtics coach uses with his team.

Grady Rivers 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 win 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.

The Lakers led for nearly 44 minutes before being caught and passed by the Celtics, who outscored them 47-21 over the final 18:04. It was a monumental collapse, and now Kobe Bryant and the Lakers, who came into the series as heavy favorites to win their 15th title, are trying to put it behind them.

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.

“I just told them as a team, they had their heart ripped out,” Jackson said. “It’s tough to recover from that, but they will. This thing is not over.”

It’s close, though, and unless the Lakers can find a way to win three games in a row, the Celtics will again rule the NBA.

It would have been impossible to imagine them or Rivers in this position a year ago. The revered Boston Celtics were a disaster.

The league’s most storied franchise had fallen on the hardest of hard times. The mystique had faded and Rivers’ young team had begun to accept defeat. The 46-year-old’s future seemed uncertain as well. There were questions about his defensive philosophies, his in-game strategies and some wondered if the former player was too chummy with his club.

It seemed as if it was only a matter of time before the ax would fall on Rivers, who spent five years with Orlando before joining the Celtics in 2004.

But general manager Danny Ainge believed in him, and that faith has been rewarded.

“Last year was a tough year,” Rivers said. “It was a tough year for me as a coach. It was a tough year for our players, and hell, I’m thankful that Danny hung in there with me more than anything.”

Rivers never thought about things not working out in Boston. He was confident in himself, and that in turn, gave his players resolve.

“When I look back to last year, the thing that I’m most proud of is that when a lot of teams have that type of turmoil and those type of losses, all you read about is usually the fights in the locker room, the whispers. We didn’t have any of that. Our players stuck together through that horrendous year.”

Rivers refuses to take much credit for the job he did this year in getting Ray Allen, Kevin Garnett and Paul Pierce, three stars aligned by Ainge through trades, to blend into one supernova. But Rivers got them to immediately buy into his system and the Celtics won 66 regular-season games, including a 25-5 mark against the supposedly superior Western Conference.

He steered them through a surprisingly tough seven-game series against Atlanta — his first playoff series win as a coach — and then past Cleveland in seven games. The Celtics got by Detroit in six before entering the finals against the Lakers, who have the game’s best player and its best coach.

To this point, Rivers has matched Jackson’s every X and O in a chess game nearing a checkmate.

Rivers, though, doesn’t see his success as personal validation.

“I don’t care to be judged, honestly,” he said. “This is a player’s game. It always will be, and it really should be. Naismith did not invent this game for us to be talking about coaches. It’s a players game and our job is to get the players to play. That’s our job.”

Do your job. Sounds like something Grady Rivers would tell his son.

The Celtics were 1-0 and in Toronto when Rivers learned that his father had passed away. He left the club to attend the funeral in Illinois and Boston’s players dedicated their win over the Raptors to their coach and his family.

Following his heart-tugging news conference, Rivers, a father of four, was asked if he dedicated this memorable a season to his father.

“I dedicated my life,” he said. “Everything I’m about is from my mom and dad. That can never go away.”

And if the Celtics don’t win Sunday, they’ll go home with two chances to wrap up the title. Game 6 is scheduled for Tuesday in Boston.

A win would be followed by a parade. Maybe as early as June 18.

On Grady Rivers’ birthday