The St. Louis Blues are headed to the Stanley Cup Playoffs for the fourth consecutive season after a 4-1 win against the Calgary Flames on Thursday.

The Blues have earned 100 or more points in each of the past three full seasons, and they are three wins shy of reaching 50 for the second straight.

A six-game losing streak to end last season cost St. Louis the Central Division title; the Blues were then eliminated by the Chicago Blackhawks in the Western Conference First Round after holding a 2-0 series lead.

The Blues are again struggling down the stretch, and their leading scorer, forward Vladimir Tarasenko, is day-to-day with a lower-body injury, but if they can get back to full strength, they are built for a long postseason run.

Here are five reasons the Blues clinched a playoff berth:

1. Top of the line

Tarasenko and Jori Lehtera were already a natural match after they played two seasons together for Sibir Novosibirsk of the Kontinental Hockey League. In early November, the Blues put them with Jaden Schwartz to form the prolific "STL Line." They have combined for 79 points when on the ice together at even strength, according to DobberHockey.com, making them one of the most productive trios in the NHL.

Jaden Schwartz Left Wing - STL GOALS: 25 | ASST: 33 | PTS: 58

SOG: 171 | +/-: 13

Injuries to Schwartz (foot) and Lehtera (concussion), and now Tarasenko, kept the trio apart at times, but they have formed one of the most dangerous lines in the League when at full strength. Tarasenko is the first Blues player with more than 50 even-strength points since Pavol Demitra (57) in 2002-03, and he's enjoyed a breakout season with career highs in goals (36), assists (35), points (71), power-play points (18) and plus-minus (plus-26). Signed to a two-year, $4.7 million contract last September, Schwartz's 58 points are a career high.

St. Louis' top line of Alexander Steen, David Backes and T.J. Oshie has also been productive; the trio was tied for fifth in March with 21 even-strength points when on the ice together. Steen's 38 assists lead the Blues, and he is tied with defenseman Kevin Shattenkirk for most power-play points (24).

2. Depth on defense

Shattenkirk is the engine that drives the defense, and his 25-game absence following abdominal surgery caused a ripple effect. The Blues scored 2.52 goals per game (20th in the League) without Shattenkirk compared to 3.14 (third) from Oct. 9-Feb. 1. At the time of his injury, Shattenkirk's 40 points were second among defensemen, and St. Louis was on a 10-0-1 run, averaging 4.3 goals per game over that span.

Kevin Shattenkirk Defense - STL GOALS: 8 | ASST: 32 | PTS: 40

SOG: 126 | +/-: 16

The Blues went 14-8-3 without Shattenkirk before he returned Saturday, keeping them in the race for the division title. The back end was fortified with the acquisitions of Robert Bortuzzo and Zybnek Michalek prior to the NHL Trade Deadline, and the returns of Shattenkirk and Carl Gunnarsson have the St. Louis defense better equipped compared to seasons past.

3. Goaltending

Given an opportunity to be the No. 1 goaltender, Brian Elliott set a Blues record March 17 with his 21st career shutout, and his 2.20 goals-against average is tied for fourth in the League. Elliott and Jake Allen (20-6-4, 2.40 GAA, .907 save percentage) have combined for 10 shutouts, second behind the New York Rangers (11), and their six road shutouts has matched the Blues record set by Jacques Plante and Glenn Hall (1968-69).

Coach Ken Hitchcock said last week that Elliott is the No. 1 goalie heading into the playoffs, a great opportunity for Elliott to improve on his six wins in 18 postseason games.

4. Killer instinct

At the end of December, the Blues were 24th in the League in penalty killing at 78.4 percent. They've since risen to 10th (83.0 percent) after killing 42 of 46 chances in March, including a season-high six kills in a 3-0 victory against the Dallas Stars on March 15. St. Louis is 28-11-5 when not allowing a power-play goal.

5. The 700 Club

In his 18th season as an NHL coach, Hitchcock remains among the elite and set two milestones this season. With his 693rd regular-season win, he passed Dick Irvin for fourth place on the all-time coaching wins list, and he later became the fourth coach in League history to win 700 games.

The Blues have made the playoffs in each of Hitchcock's four seasons, but have yet to advance beyond the second round. This may be Hitchcock's best chance to reach the conference finals for the first time since he did so with the Philadelphia Flyers in 2003-04.

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