McCarthy, who stayed behind in camp when the D-backs traveled Down Under, worked a spring-high six innings Wednesday, allowing three runs on six hits and a walk while striking out six. He finishes his spring with a 2.70 ERA and will make his regular-season debut against the Giants on Monday for the club's home opener.
As for Samardzija, he was scheduled to only go three innings Wednesday in his final spring start before Opening Day. He surrendered one run on four hits.
"I always give compliments to this team," Samardzija said of the D-backs. "It's a great battle every time and a great last tuneup before the season starts."
The right-hander, who will make his second straight Opening Day start Monday in Pittsburgh, said he's happy with his offspeed pitches, which he hopes will only improve once the Cubs leave the dry desert.
"The splitter will get better as the season goes along and the more north you get," he said.
The D-backs jumped on the board first in the second inning when back-to-back hits off Samardzija from Martin Prado and Miguel Montero to start the frame led to an A.J. Pollock sacrifice fly two batters later.
The Cubs answered to snatch the lead in the top of the fourth by hanging a two-spot on McCarthy, stringing together three hits in the inning, including RBI knocks off the bats of Nate Schierholtz and Welington Castillo.
Trailing 2-1, the D-backs went ahead for good in their half of the fourth courtesy of Trumbo's opposite-field, wind-assistant two-run homer to right field off Cubs left-hander Chris Rusin.
After tacking on two more runs in the fifth, the D-backs launched three homers in the sixth to break the game open. Rusin, competing for the fifth spot in the Cubs' rotation, was charged with nine runs on 10 hits over 2 2/3 innings.
Up next: The Cubs will play their final game at new Cubs Park on Thursday, facing their intracity rivals, the White Sox, with an early 1:05 p.m. CT start. Travis Wood, who will start the Cubs' home opener April 4 at Wrigley Field, is scheduled to start and make his final regular-season tuneup. The Cubs have one more chance to set the Cactus League record in attendance. They've drawn more than 15,000 in five games this spring at the new ballpark in Mesa. The game will be broadcast on WGN Radio.