Nick Buckner belted an RBI double in the top of the 10th as the White Sox beat the Cards 4-3 Sunday at Cardinal Park.
Bristol led 3-2 with two outs in the ninth when Mercado launched a shot to left field off of Cesilio Pimentel to tie the game.
Then Cards relief pitcher Jonathan Escudero (0-1) issued a leadoff walk, and it proved fatal. Jerrick Suiter stole second base before Buckner grounded a double to right field.
Johnson City went down in order in the bottom of the 10th.
Buckner went 3 for 4 with two RBIs to raise his batting average to .303. Maximo Rivera had a home run for the White Sox.
Chris Rivera went 3 for 5 for the Cards. Mercado finished with two hits.
Pimentel (2-1) worked three innings of relief for Bristol. Mercado’s homer was the only hit he allowed and he earned the victory despite blowing the save.
The two teams will meet again today at Cardinal Park at 7 p.m. Johnson City’s Landon Beck is scieduled to start against Bristol’s Hector Garcia (0-3, 3.31).