Drew Stafford could have used Sherlock Holmes as a linemate Saturday. “This game’s a mystery,” Stafford said. A couple of things had the Buffalo forward puzzled. The first was how the Sabres could look so good at the start and just throw it away during a 4-3 overtime loss to Ottawa. The other was personal. He’s struggled mightily to score all season, so he had no idea how he recorded his first multigoal game when he wasn’t even trying to find the net. “It’s an absolute mystery,” he repeated. The opening dilemma is much easier to solve. The Sabres turned the puck over and got outworked during the second period, and the oft-seen sleepwalk resulted in a 2-0 lead transforming into a 3-2 deficit. “The first was probably one of our best periods of the year, and the second was probably one of our worst,” interim coach Ron Rolston said in First Niagara Center. “We must have just got comfortable. We can’t afford to be comfortable as a team right now, so it’s definitely disappointing.”