But Webber warned: "They (Red Bull) will get back to Mercedes' level.
"They need some time, but it's normal," he told the Austrian newspaper Salzburger Nachrichten. "You can't win for 15 years in a row.
"Everyone's saying they're not strong because they're finishing second or third, and Red Bull did do a lot of winning (in the past) but I'm sure they will win again this year.
"Whether they win enough to win the championship, we will have to see how strong Mercedes is to get too many points in the first part of the season," added Webber.
After wins in Melbourne and Malaysia, Mercedes' advantage appears even greater in Bahrain for round three, but Webber suggested that is because of the German marque's power advantage on long straights.
"Mercedes will continue to dominate the next races," he is quoted by Speed Week, "but Red Bull will win in Monaco."