"They were better than us in every situation and we didn't play well from the start to the finish and we have a ways to go," MacLean said. "I give a ton of credit to Colorado for the way that they played."
The Avalanche improved to 3-1, going 4 of 6 on the power play.
"It's always important to get everyone going," said Landeskog, the second overall pick in the June draft. "Tonight was one of those nights where you got the bounces and gave us confidence to move forward."
Milan Michalek had a power-play goal for Ottawa. The Senators are 1-3.
Craig Anderson, playing his first game against his former team, stopped 32 shots.
"We weren't at our best," Anderson said. "It's a game about momentum and when you lose momentum how do you get it back and obviously we didn't get it back very often."
Landeskog also scored Wednesday night in the Avalanche's 3-2 shootout victory in Columbus.
"The game against Columbus kind of glued the team together," Landeskog said. "It really got us going and gave us confidence and we picked right back up. Our momentum just carried us through the game."
The Senators took the lead for the first time this season on Michalek's power-play goal early in the first, but it was short-lived as the Avalanche tied it 3 minutes later on Hejduk's power-play goal.
Colorado took the lead midway through the period when Landeskog beat Anderson from in close.
The Senators wore their heritage jerseys for the first time. ... Semyon Varlamov started in goal in Colorado's first three games.
Copyright by STATS LLC and The Associated Press
Arena: Canadian Tire Centre Location: Ottawa, Ontario
Referees: Eric Furlatt, Ghislain Hebert Linesmen: Mark Shewchyk, Pierre Champoux
Attendance: 19,239 (104.0% full)
Team Stat Comparison
Power Play Goals
Power Play Opportunities
Shots on Goal
Milan Michalek (3)
(Power Play) Assists: Erik Karlsson, Sergei Gonchar
Milan Hejduk (2)
(Power Play) Assists: Erik Johnson, Paul Stastny
Gabriel Landeskog (2)
Assist: Ryan O'Reilly
Joakim Lindstrom (1)
Assists: Ryan Wilson, Matt Duchene
Matt Duchene (1)
(Power Play) Assists: Gabriel Landeskog, Ryan O'Reilly
Daniel Winnik (1)
(Shorthanded) Assist: Shane O'Brien
David Jones (1)
(Power Play) Assists: Milan Hejduk, Erik Johnson
Joakim Lindstrom (2)
(Power Play) Assists: Ryan Wilson, Ryan O'Reilly