TAMPA — Coach Jon Cooper joked before Monday night’s game that playing the Islanders is like Groundhog Day — “They play the same way and they’re good at it.”It might be starting to feel like Groundhog Day for the Lightning in a different way. They again played good hockey, but made costly mistakes and lost. It’s been a downward trend.This game didn’t look as bad as the 5-1 score, after the Islanders piled on a couple of late goals. But even without those last two, the Lightning made enough mistakes to lose it.“We need to eliminate those one, two big mistakes we’re making that are giving teams that cushion,” Kevin Shattenkirk said. “We’re in games if we eliminate those mistakes.”The Islanders’ second goal was the Lightning’s worst moment. They had a power play and entered the zone four-on-two. Nikita Kucherov had an opening for a quick shot off the rush, but passed to Steven Stamkos in the left circle. Johnny Boychuk went down to block the shot, and Stamkos couldn’t get the shot off. This is where things got bad.All four Lightning forwards had crashed the net and were down at the goal line as the puck deflected back the other way. Victor Hedman sank low to go for the puck, while Casey Cizikas dove and swiped at the puck, chipping it up the ice.Now, Josh Bailey had a step on Hedman, who had to turn around, and thus a breakaway. Instead of a power-play goal to tie the score, the Lightning gave up a deflated shorthanded goal and were down by two.“We gave it to them,” Cooper said. “It’s a lot of things (that broke down on the play).”The Islanders scored timely goals. That shorthanded breakaway was their second in less than two minutes.The first came off a play that started with a Lightning breakaway. Hedman threw an outlet pass from deep in his own zone to the opposite blue line for Cory Conacher. Semyon Varlamov made a pad save on Conacher, however, and the play immediately shifted back the other way.Ryan Pulock picked up the loose puck and fed it up to Ross Johnston, who had a two-on-one with Bailey. Mitchell Stephens caught up to the play to eliminate Bailey. Luke Schenn laid out to block the shot, and Johnston elevated a wrister over him to put the Islanders on the board first.That one was not a Lightning mistake, but an opponent taking advantage of an opportunity for a timely goal. That’s something last year’s Lightning did a lot of.Islanders coach Barry Trotz credited his team’s “killer instinct,” something the Lightning recently said they need more of.The Islanders’ third goal came off a weird bounce along the wall, not a mistake as much as luck, but still not a perfectly-played puck that turned into a two-goal lead.To make matters worse, the Lightning thought they had come within a single goal a few minutes later, only to have it yanked away. Victor Hedman scored, but the Islanders challenged for offsides and they were right.“It was too bad because we need those,” Cooper said. “But it wasn’t just offside, it was way offside.”Stamkos pointed out the many chances the Lightning had. They took 32 shots, hit the post at least four times, and had a lot of shots blocked. But those chances didn’t go in.On the other side, the Islanders had all facets clicking — both sides of special teams, defense and scoring. The Lightning haven’t been able to string all three of those together; they’ve had pieces.“They were the more opportunistic team tonight,” Shattenkirk said. “We can’t beat ourselves up when we’re creating chances like that. But there are a couple of mistakes we need to address."