The right-hander, widely considered one of baseball's elite hurlers, took the mound for the Jays in the series opener.
"You just hope you catch him on an off day and we hope today is his off day," Washington said.
Washington and the Rangers' hopes were indeed fulfilled as Halladay was not at his best in Tuesday's contest. Using a pair of well-timed home runs, the Texas offense took advantage of Halladay's mistakes en route to a 5-4 victory at Rogers Centre. The win was the Rangers' first in four tries on the road this season.
With the game tied in the seventh inning, Rangers second baseman Ian Kinsler continued his red-hot hitting with an opposite-field home run against Halladay that cleared the right-field wall and gave Texas a 5-3 lead that the club did not relinquish.
"[Kinsler] put a real good swing on it and it left the ballpark," Washington said. "There's the difference right there."
Texas (6-7) also took the Toronto right-hander deep in the second inning, when right fielder Nelson Cruz lifted an 0-1 sinker from Halladay into the left-field stands for a two-run shot. It was Cruz's team-leading sixth home run of the season. He is one ahead of Kinsler, who has five homers on the year.
"Timely hitting, that's what I'm talking about," said Rangers outfielder Marlon Byrd. "When he makes mistakes, we have to get on him and the couple mistakes that he made, we made him pay.
"That guy battles out there. If you're not ready mentally, he will eat you alive."
The Texas hitters certainly were mentally prepared against Halladay (3-1), notching eight hits and five runs off him to hand the veteran his first loss of the season. Halladay's career 5.36 ERA against Texas is higher than any other opponent in the American League.
"There's obviously some good hitters in their lineup," said Halladay. "That's the tough part -- they have the ability to hit home runs, especially when you don't make quality pitches."
The Rangers opened the day leading the AL in home runs, with 24, and added to that total following the blasts from Kinsler and Cruz.
"I guess because [Halladay's] one of the best pitcher's in the league, we tried to get fully focused and tried to do better," said Cruz.
The benefactor of the Rangers' home runs was Texas starter Brandon McCarthy, who earned the victory. Pitching with wavering command at times, McCarthy allowed three runs on six hits over six innings. He walked two, struck out two and needed 97 pitches in the outing.
"He was able to make pitches when he had to and he kept the damage to a minimum," Washington said of his starter. "They scratched one run at a time off him and he did a great job."
McCarthy didn't know exactly what to make of his outing.
"It's a hard one to kind of put my fingers on," McCarthy said. "There were some good things about it and some bad things. I didn't feel sharp necessarily, in terms of fastball command, and slider command. But I felt like I battled and did what I could to keep us in the games."
McCarthy also got some help from the Rangers bullpen. While he did leave the game with a 5-3 lead, one unearned run, courtesy of an error by shortstop Elvis Andrus, allowed the Jays to bring the score to 5-4.
However, the Blue Jays (10-5) could not tie the game against Rangers closer Frank Francisco, who was brought in during the eighth inning for what turned out to be a five-out save. Francisco ran into some trouble in the frame, loading the bases, but just as easily managed to get himself out of the threat.
With one out and the bases full in the eighth, the hard-throwing right-hander induced a lineout from Rod Barajas and then an inning-ending fly ball off the bat of Travis Snider.
In the ninth inning, Francisco did allow a double to Jays second baseman Aaron Hill, but other than that he breezed through the inning to earn his second save of the year.
Washington was more than happy with the closer's outing.
"I thought Frankie was as tough as he's ever been," said Washington. "He did what he's capable of doing. It's just that he had to extend himself to do it and we're very happy for it."
David Singh is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.