MIAMI -- For the better part of the past four years -- even as LeBron James racked up regular-season and postseason MVP awards during four straight runs the NBA Finals -- Miami Heat coach Erik Spoelstra repeatedly referred to Chris Bosh as the team’s most important player.

And each time, the muffled scoffs and eye-rolling would follow from those within earshot.

But Spoelstra always felt there was a clear distinction between LeBron’s value and Bosh’s impact.

“I don’t expect everyone to always understand it,” Spoelstra would say at least once every couple of weeks. “But in terms of what we do, how we want to play, what we need to happen on the court on both ends for us to be successful, C.B. is our most important player. That’s how we see him.”

What Spoelstra saw then is becoming abundantly clear to many now.

Bosh is off to the most productive three-game start of his Miami tenure, and the Heat have emerged from the first full week of the regular season as the lone unbeaten team in the Eastern Conference after Sunday’s 107-102 victory against Toronto.

While Bosh refuses to buy into the notion that LeBron’s departure to Cleveland in free agency is solely responsible for his initial statistical outburst, the 12-year veteran believes his development is part of a natural progression in his game that was inevitable, regardless of Miami’s personnel.

In other words, after four straight seasons of seeing his scoring and rebounding numbers decline as he settled into a role as primarily a spot-up shooter, something had to give.

“It’s just time,” Bosh said after he finished with 21 points, 11 rebounds and four assists in 38 minutes against the Raptors. “I knew I couldn’t settle into that same position I’ve been in the past four years, floating outside and shooting a couple of jumpers. I know I had to switch it up a little.”

Chris Bosh has helped filled the void left by LeBron James with increased productivity. Robert Mayer/USA TODAY Sports

Through three games, Bosh has switched it up a lot. He’s averaging 25.7 points, 11.3 rebounds and 4.0 assists per game while shooting 54.5 percent from 3-point range. Having accumulated totals of 77 points, 34 rebounds, 12 assists and four steals so far, Bosh is off to his most dominant start since he arrived in Miami in 2010 to essentially become the third option behind LeBron and Dwyane Wade.

This represents the fastest start for Bosh since his final season with the Raptors to begin the 2009-10 season, when he tallied 93 points, 44 rebounds, made all three of his 3-pointers and shot 45 free throws. Bosh has been fond of saying that even though his overall numbers dropped off once he arrived in Miami, that he is a much better player now than he was during his previous All-Star years in Toronto.

Raptors guard DeMar DeRozan was a rookie during Bosh’s final season in Toronto, and said there are aspects of his former teammate’s game that have expanded despite being featured far less in Miami.

“He was scoring 40 and doing all types of amazing things back then,” DeRozan said of Bosh, who averaged career-highs of 24 points and 10.8 rebounds for the Raptors the season before he opted out of his contract to test free agency in 2010. “It’s a tough question, but I think [Bosh is a better player now]. He’s still the same type of [dynamic] player, but he’s a lot better now than he was, a lot more mature.”

Bosh pointed out some specific areas where he felt his game has grown this season.

It starts with conditioning and consistency.

“For me, that’s what this year is all about,” Bosh said. “Before, I’ve had good starts or whatever, but I couldn’t keep it up. I ran out of gas. I’m just focusing now on playing it one game at a time and making sure I can sustain what I’m putting out there.”

Another facet of Bosh’s game that hints at expansion is his ability to make plays with the ball. He now gets many of the initial touches in halfcourt sets and has multiple options. His shot has comfortably extended out to 3-point range the past few seasons, but he also maintains a quickness advantage in majority of his matchups at center that allows him to get by opponents with his first step.

“More than anything, I’m a facilitator now,” said Bosh, who combined with Wade for 40 points, 22 rebounds and 11 assists Sunday. “I can find open guys a lot better. I can develop chemistry a bit better. I can work off catch-and-goes. I can work off the ball. All those things make me a bit more complete.”

But there’s nothing Bosh takes more pride in so far than his ability to get to the free-throw line, where he’s averaging nearly 10 attempts through the first three games. Still, Bosh and the Heat know better than to exude overwhelming confidence. The sample size is too small and a bit flawed at this point.

The Heat won their season opener against a Washington team that was missing two of its best three players, with guard Bradley Beal sidelined with a broken wrist and center Nene having served a one-game suspension. Miami’s second win was against a Philadelphia team that could be contending for the NBA’s worst record for a second consecutive season. Sunday’s game saw Bosh face a Raptors frontline that was without injured shot-blocker Amir Johnson.

But the Heat’s offense seems well ahead of schedule, with Miami averaging 109.3 points per game to rank second in the league behind Golden State. After finishing with 33 assists on Saturday against the Sixers, the Heat added 22 more to complete the back-to-back set Sunday. It has been an encouraging blend of ball-movement, back-to-back availability from Wade and bigger boosts from Bosh to begin the season.

“The best part about it is it hasn’t been strenuous,” Bosh said of the additional burden. “It feels natural.”

The schedule will bring tougher tests, with five of their next six games against teams that made the playoffs last season, beginning with Tuesday’s visit from the Houston Rockets.

“We’re three games into this, so it could quickly go the other way if guys start to feel comfortable,” Spoelstra said. “That’s not a referendum on our personnel. Guys see how we have to play to be successful.”

Continuing to play through Bosh is a start.

Especially considering the way he has started the season.

Sustaining it is the next test for Bosh and the Heat. But even a team that’s advanced to the NBA Finals the past four seasons and has won two titles in the span isn’t too proud to be pumped by opening 3-0.

Bosh insists it means something.

“Absolutely, we humbly take it,” he said. “We’ve been saying we want to get off to a good start. It’s about to get tougher. But it’s important for us to get going, hit the ground running. We just have to keep our head down, even though [critics] will come out and start saying how surprised they are. We just have to keep focusing on that day’s work and making sure we’re being the best team we can be.”