TAMPA — So much momentum in Game 1 shifted in a two-second span at the end of the first period, where instead of a tie game, the Lightning found itself down 2-0 after allowing a power-play goal to Alex Ovechkin with six seconds left.Steven Stamkos said he knew that Nikita Kucherov's tying goal would be waved off due to having six men on the ice. What bothered him more was how Washington was able to do what it wanted immediately on the ensuing power play that sent the Capitals on their way to a 4-2 victory Friday at Amalie Arena.RELATED: More Lightning coverage"We were six men by a mile, so I don't think anyone was too fired up about the goal. It had been blown dead for a while," Stamkos said. "Any time you give up a goal like that, it gives momentum to the other team. It's just execution. Right off the draw, we know what they're trying to do. They're trying to get it to Ovechkin for a shot. We were just a step behind today, and you can't do that this time of year against a quality opponent."The Lightning had struggled in the opening period, but D Ryan McDonagh made a long pass to Kucherov for a breakaway and a highlight-reel tying goal. But that goal was quickly waved off, and two seconds later, Washington had a 2-0 lead, thanks to the NHL's leading goal-scorer from the regular season.Ryan Callahan said there was much more at fault in the Lightning's loss than that change in momentum in what ended up a 4-2 loss on home ice."That was obviously part of it, giving up a late power-play goal with a couple seconds left," Callahan said. "But the whole game wasn't good enough for where we need to be this time of year. … By no means was that a tipping point or momentum turn. I don't think we had a good enough game the entire 60 there."StifledAfter the two-shot first period, the Lightning had only eight in the second period for 10 total entering the third as Washington dominated. Tampa Bay finished with 21, a playoff low and only two above the low for the entire regular-season.Stamkos didn't get a shot on goal until the third period, and Brayden Point and Alex Killorn, two key scorers in the playoffs, had no shots on the night.Off earlyWith Washington up 4-0, the Lightning put backup Louis Domingue in net for the third period, giving Andrei Vasilevskiy an early exit. He faced 25 shots and stopped 21.The relief appearance marks the playoff debut for Domingue, who had played in 96 regular-season games, but never one in the postseason.ShorthandedWashington played so well without C Nicklas Backstrom, who also missed the final game of the Penguins series with a hand injury. … Tampa Bay had C Anthony Cirelli (undisclosed) and C Cedric Paquettte (hand) sidelined briefly during the second period, but both were back on the bench and playing in the third.Bolts bitsFormer Bucs DT Chris Baker, cut by Tampa Bay after he managed 0.5 sacks last season, was back in Tampa and wearing a Capitals jersey. He played for the Redskins before signing with the Bucs last year. … Tampa Bay had won eight straight playoff games against Washington going in. They won the last four in 2003 for their first-ever playoff series win, then swept the Capitals in four in 2011.Contact Greg Auman at [email protected] and (813) 310-2690. Follow @gregauman.