Jimmy Butler is adamant the best is still to come from the Miami Heat after they reached the NBA Eastern Conference finals for the first time since 2014 by eliminating the Milwaukee Bucks.

The Heat came into the playoffs ranked fifth, making them the lowest seed to reach the Eastern Conference finals in 21 years.

The Bucks came into the playoffs as the conference's top seeds, but a 103-94 Heat victory in Tuesday's Game 5 secured a 4-1 triumph for Erik Spoelstra's team.

Butler certainly played his part in the series-clinching win, registering a double-double of 17 points and 10 rebounds after a shaky first quarter, and he was in a confident mood after the game.

When asked if the Heat had shown their best in the five meetings with the Bucks, Butler said: "No, I don't think so. I don't think we've played a full 48-minute game yet, and that what's promising.

"When we do lock in and decide to play from start to finish, I think the game would be a lot easier. I don't think it's happened yet, but we have to next round."

With regards to leading the team to the conference finals, Butler added: "It means a lot, but like you said, that's not my goal. That's not my guys' goal. It's not the organisation's goal.

"We want to win it, win a championship, and I think that's what we're focused on. These next eight are going to be much harder than the previous eight. We know that, but we're ready."

The Heat were boosted by Giannis Antetokounmpo missing out for the Bucks as he failed to shake off an ankle injury.

But Spoelstra was no less proud of his side, applauding them for their "journey".

"I want our guys to just step back at least for a night, if not two nights, and just reflect," Spoelstra said.

"It's not easy to get to the conference finals, and our organisation knows that. We've been trying desperately to get back to the conference finals. It's not our ultimate goal, we get it, but you can still acknowledge the journey, how hard it is to this point.

"That is why we brought Jimmy Butler here. That is why we put this team together with the veterans, adding Andre [Iguodala] and Jae [Crowder], building around Goran [Dragic] and Bam [Adebayo], having a young core.

"It was to try and do something in the playoffs. It's not easy to get to the conference finals. Otherwise, every team would be doing it."