CHICAGO -- The Chicago White Sox fell 5-4 to the Tampa Bay Rays on Monday in the opener of a three-game series and have now lost four of their past five games.

How it happened: The Rays' Mikie Mahtook, batting all of .188, delivered the go-ahead RBI single in the ninth inning off White Sox reliever David Robertson. In trying to score the game-tying run in the ninth inning, Alexei Ramirez was easily thrown out at the plate by Rays center fielder Kevin Kiermaier. Carlos Sanchez hit a two-run home run in the seventh inning to put the White Sox up a run, but the Rays scored in each of the final two innings. Jose Abreu tied the game in the sixth inning on a two-run home run to center field. White Sox starter Jose Quintana gave up two runs on seven hits over six innings with seven strikeouts.

What it means: First it was the starting staff that struggled uncharacteristically during the most recent series against the New York Yankees, as Carlos Rodon and Jeff Samardzija were hit hard. In the series opener against the Rays, it was the bullpen's turn to get knocked around. All three White Sox relievers -- Jake Petricka, Zach Duke and Robertson gave up runs to the Rays in the late innings. The bullpen had a 2.49 ERA over its previous 26 games, but had shown signs of cracking with a 4.86 ERA over their previous four games.

Outside the box: Two hits for Abreu extended his most recent hitting streak to 14 games. The co-American League player of the week, along with Adam Eaton, has six career hit streaks of 13 or more games. Abreu also has hit five home runs over his last 11 games.

Off beat: Officially Avisail Garcia was charged with one error in right field, but it could have easily been two. Garcia let a drive to right field by Joey Butler clank off his glove for a fifth-inning double and Butler eventually scored. In the seventh, pinch hitter Grady Sizemore led off with a double and Garcia's throw back to the infield short-hopped Sanchez. Sizemore advanced on the play and also scored.

Up next: The White Sox will send left-hander Chris Sale (9-6, 3.20) to the mound Tuesday in the middle game of the three-game series. The Rays will counter with right-hander Chris Archer (9-8, 2.54) in the 7:10 p.m. CT start from U.S. Cellular Field.