ST. PAUL, Minn. — Ross Colton and Parker Kelly each scored in the third period for Colorado, an opportune time for their first goals of the postseason as the high-scoring Avalanche snapped back from a midseries lull and beat the Minnesota Wild 5-2 in Game 4 on Monday night to take a 3-1 lead in the second round of the NHL playoffs.“It’s just about staying ready,” Kelly said, “and all these guys in here are ready.”Mackenzie Blackwood made 19 saves in his first start this postseason after relieving Scott Wedgewood during a 5-1 loss in Game 3 on Saturday, and the Avalanche moved within one win of taking the first spot in the Western Conference finals. Game 5 will be in Denver on Wednesday.“You’re never going to be perfect after 30 days off, so I just try to do my best to stay sharp,” said Blackwood, who learned the day before he would be starting.Nazem Kadri scored on a power play in the second period, and Nathan MacKinnon — who had a brief absence to fix a bloody nose from a puck to the face — and Brock Nelson added empty-net goals in the final minute. Nico Sturm tied the game at 2 for Minnesota with his first goal of the postseason about two minutes after Colton scored, but the Wild were outshot 20-4 over roughly the first half of the game by an energized Colorado offense.Rookie Danila Yurov scored his first career postseason goal on a deflection midway through the first period for the Wild during a four-minute power play prompted by a double minor penalty on defenseman Josh Manson, but they failed to consistently get pucks dee …