NHL updated series odds: Value with 'dogs in best of 3s

The Stanley Cup semifinals have delivered. Both series are down to a best of three for a spot in the final, with six of the eight games so far decided by just one goal.

Oddsmakers pegged each series to be lopsided, with the Lightning -300 favorites over the Islanders and the Golden Knights an almost unheard of -500 to beat the Canadiens.

They've been anything but one-sided through four games a piece, but oddsmakers have refused to change their stance. Will the favorites pull away, or will the underdogs continue to shine?

Lightning (-240) vs. Islanders (+200)

The Islanders were dealt a bit of a lucky hand to help them come out of the East Division. At five-on-five, they owned just a 46.3% share of the expected goals against the Penguins and a 46.4% share against the Bruins. They were outshot and outchanced through the first two rounds, but the downfall of Tristan Jarry and Tuukka Rask afforded them a clear lane to the semifinals.

However, they've grown stronger as these playoffs have worn on, and there's been nothing lucky about the Islanders' success against the Lightning. New York has controlled an exceptional 57.7% share of the expected goals at even strength in the series. That number has only dropped to 55.5% at all strengths as the team has contained a Tampa Bay power play that looked unstoppable through two rounds.

While the Islanders' top players don't get the same recognition as the Lightning's, they've been the better group in this series. Mathew Barzal has been the best player, with three goals and a ridiculous 78.18 xGF% against Tampa Bay. The top four players in expected goal share in this series are all Islanders. Three of their six defensemen have over a 60% share, while five of six are above 50%.

Conversely, Jan Rutta leads all Lightning defensemen with a 50% share. Three Tampa Bay blue-liners sit below the 40% mark. Also, Victor Hedman's injury is seemingly hampering his effectiveness. This team isn't the same without Hedman dominating on the back end.

The key here for the Islanders - this season's second-least penalized team - is to stay out of the box, because at five-on-five, Barry Trotz and Co. have figured out how to beat the Lightning. It would be ludicrous to lay -240 on a Tampa Bay team that's been second best through four games.

Pick: Islanders (+200)

Golden Knights (-360) vs. Canadiens (+300)

This series has largely mirrored Tampa Bay versus New York. Despite being overwhelming underdogs, Montreal has left little doubt it belongs in the final four. At five-on-five, the team owns 54.3% of the expected goal share and has generated 50 high-danger chances to just 34 for the Golden Knights.

The Canadiens have kept Vegas to the outside and away from the front of the net while using their speed to pose a consistent threat in transition. The Tyler Toffoli-Nick Suzuki-Cole Caufield line has been dominant, as has the Artturi Lehkonen-Phillip Danault-Brendan Gallagher trio. All six players have an expected goals share above 57% at five-on-five, with three of them over 67%. They've outplayed the Golden Knights' top six, which hasn't scored in this series.

Enough can't be said about the work the Danault line is doing. After shutting down Mitch Marner and Auston Matthews in Round 1, it's doing the same thing to Mark Stone and Max Pacioretty, who've combined for two points. Stone's 31.3 xGF% in this series is the lowest among all skaters. Pacioretty's isn't much better at 38.3%.

Vegas has received timely scoring from the back end to stay even in the series - seven of its 10 goals have been scored by defensemen - but that's not a sustainable method for success. Until Peter DeBoer can make the necessary adjustments to penetrate Montreal's stubborn defensive structure, this series will continue to be played to the Canadiens' tune.

Furthermore, while it's impossible to account for officiating when capping a game or series, you have to assume power-play opportunities will be about even. That's hardly been the case thus far. Vegas has been the biggest beneficiary of some glaring missed calls. The Golden Knights have enjoyed a rare 11-6 power-play advantage, a gap that's sure to be much more even over the final three games. There's a lot working in the Canadiens' favor, and we get them at a generous price to boot.

Pick: Canadiens (+300)

Alex Moretto is theScore's supervising editor of sports betting. Find him on Twitter @alexjmoretto.