As part of the A-Line with Petr Sykora and Jason Arnott, he helped lead the team to the 1999-2000 Stanley Cup championship. The following year he scored a team record 96 points in the regular season, third best in the league. He also played a key role in helping New Jersey win the Stanley Cup in 2002-03.
During the 2004-05 NHL lockout, he played hockey in Russia, where he contracted Hepatitis A. His bout with the disease severely weakened him, resulting in a weight loss of 30 pounds, and keeping him out of NHL action after the lockout was resumed.
Three months into 2005-06 NHL season, he made his first appearance of the season on January 3, 2006, against the Florida Panthers, resuming his role as an alternate captain (replacing Alexander Mogilny). He picked up where he left off, scoring eight points in his first four games and helping the Devils win his first nine games back with the team. Paired with Brian Gionta and Scott Gomez to form the "EGG Line," Eliáš helped the team instrument a historic comeback and win the Atlantic Division title, despite being 19 points out of first place when he returned in January. In the first game of the 2006 playoffs against the New York Rangers, he became the 10th player to score six points in an NHL playoff game, with two goals and four assists. Elias's 2006 postseason campaign was spectacular, even though the Devils were eliminated by eventual Cup champions, Carolina, in the second round. Elias scored 6 goals and added 10 assists for an impressive 16 points in just 9 games.