Improbable and unforgettable. That is how a Wednesday night in FedExForum at the close of February will be remembered when the Grizzlies look back on this regular season. The Griz tossed aside a 25-point deficit and changed the makings of a lopsided loss with their defense to earn a dramatic 90-84 victory over the Dallas Mavericks before 16,017 fans who still might be wiping their eyes in disbelief. “Grit, grind, heart, sacrifice I could name 10-15 words (to describe) this,” forward Zach Randolph said after the Grizzlies extended their winning streak to eight games. “It was one of those games.” A game in which: • Griz coach Lionel Hollins called time out twice in the first 3 ½ minutes. • The starters were benched in the first five. • The Mavs racked up 38 points in the opening period and enjoyed a 51-29 lead with 5:25 left in the second quarter. • Memphis outscored Dallas 36-4, which included a franchise record 24 unanswered points, during a stretch that bridged the second and third quarters. • Dallas looked feeble throughout a five-point third quarter — a Memphis franchise-record low for an opponent in any quarter. “A lot of it was pride,” Griz point guard Mike Conley said. “We felt the grumbling in the stands. We were embarrassed.” The Griz trailed 10-0 before fans could get settled in their seats. Hollins reacted quickly because he had seen the lackadaisical attitude at shootaround and during practice the day before.