Indianapolis (63-52) scored all four runs in the fourth off Bisons southpaw T.J. House. Trailing 2-0, Danny Ortiz ignited the outburst with a one-out double into the right-field corner. Following a strikeout, Jacob Stallings laced a run-scoring single into right-center to make it 2-1.
Indy's two-out rally was prolonged by a Kevin Newman single and Max Moroff's third walk of the game, setting the table for a two-run single up the middle off the bat of Luplow. Edwin Espinal capped the inning with an RBI single to right.
The score remained 4-2 until Luplow opened the bottom of the seventh with an opposite-field dinger, his sixth Triple-A blast and 22nd overall in 2017.
Buffalo (50-66) brought the go-ahead run to the plate in their final at-bat, but Dan Runzler struck out Rowdy Tellez with runners on first and second to seal his fifth save in as many chances.
Clay Holmes (8-5) worked the first five innings for Indy, allowing two runs on six hits and a walk with three punchouts. Tyler Eppler took over in the sixth and departed with two outs in the ninth. He was charged with one run on four hits in 3.2 innings pitched.
House (8-11) fell to 3-7 in 13 road starts after surrendering four runs on seven hits over 5.1 innings of work.
Luplow and Espinal finished a combined 4-for-7 with four RBI in the heart of the order.
Indianapolis' four-game winning streak is its sixth of at least four games this season. The Tribe have also strung together a six- and eight-game winning streak.
The Indians and Bisons wrap their three-game series Wednesday afternoon at the Vic. The Tribe will send right-hander Drew Hutchison (6-7, 3.78) to the mound. First pitch is set for 1:35 p.m.
This story was not subject to the approval of the National Association of Professional Baseball Leagues or its clubs.