Markstrom made 21 saves in the first period but allowed four goals in the second period and did not finish the game in a 4-1 loss at Rogers Place on Sunday.
"We all know that we weren't good enough in front of him," Flames defenseman Rasmus Andersson said. "What, three 2-on-1s for goals? We leave him out to dry. How many odd-man rushes did they have today, especially in the second period, and they capitalized. It just wasn't good enough and it cost us."
After a scoreless first period that saw the Flames outshot 21-7, the Oilers broke through in the second, led by forward Evander Kane, who had a natural hat trick in 6:00.
Markstrom made 30 saves in Game 3 before being relieved at the start of the third period by Dan Vladar, who made seven saves in relief. Markstrom allowed five goals on 40 shots in a 5-3 loss in Game 2, and six goals on 28 shots when the Flames won 9-6 in Game 1. He has a 5.74 goals-against average and an .853 save percentage in the best-of-7 series, which Edmonton leads, 2-1. Game 4 is here on Tuesday (9:30 p.m. ET; ESPN, CBC, TVAS, SN).
"What were they, four odd-man rushes, I think?" Calgary forward Matthew Tkachuk said. "I thought he was awesome tonight, Markstrom]. He made so many great saves and kept us in it in the first, and we didn't play that great in front of him in the second."
***[RELATED: [Complete Flames vs. Oilers series coverage]*
Oilers center Connor McDavid assisted on three of the four goals scored in the second period Sunday and his speed on the attack was a repetitive theme, catching the Flames out of position and on their heels frequently. McDavid has nine points (two goals, seven assists) in the series.
Kane, and McDavid's other linemate, Leon Draisaitl, combined for 10 points in Game 3. Draisaitl set a Stanley Cup Playoffs record with four assists.
"We've let one guy beat us a few nights now," Tkachuk said. "Back to the drawing board and figure out a way to stop him next game."
Tkachuk said the issue has been more than just having McDavid wheel around freely in the Flames zone.
"I think it more starts from our offensive zone when we're maybe turning it over or having not the best line changes and letting them gain speed through the neutral zone," he said. "From what I can remember, they had four rush goals tonight.
"They've got one player that plays half the game (McDavid played 15:49 through two periods) and is playing some great hockey right now. We've got to find a way to stop that. When we get in their zone, we've got to hold pucks, nothing blind, and get shots to the goalie. That's where they can have some trouble, with rebounds and loose coverage with that. (We) just have to have consistent O-zone shifts and not throw anything blind where they can feed their transition."
Calgary trailed 2-1 in their first-round series against the Dallas Stars but rallied to win in seven games. The sentiment from the players after Game 3 against Edmonton was they're determined not to let one game, especially one period, decide the series.
"Obviously, it's a long series," Andersson said. "That's the beauty of the playoffs; it's a new game in a day and a half and we're excited for that. Now we flip the page, we move on."
Flames coach Darryl Sutter said they'll need to create more speed, not just try to contain McDavid, in Game 4.
"Give Edmonton credit the way they played in neutral [zone] and it fed [McDavid's] game for sure," Sutter said. "It was more of them slowing us down. That's what they did a good job of."
