He made an impression on his former team Sunday.
The left-hander held the Orioles hitless for six innings before allowing Steve Pearce's leadoff homer in the seventh inning for Baltimore's only hit, and the Chicago Cubs won 2-1 for a three-game sweep.
"I knew a lot of the players on their team. I feel like I let people down not being able to be a factor on the team," Wada said through a translator. "So I try to be the player that they thought they acquired."
Wada (4-1) got a popout after the homer that landed on Waveland Avenue and departed to a standing ovation from the crowd of 32,774. In his eighth career start, he struck out a career-high eight and walked one in 6 1-3 innings. He retired 16 straight after Adam Jones drew a two-out walk in the first.
"I feel appreciated they honor me even though I allowed that home run," said Wada, who never threw a no-hitter in Japan.
Wada was 5-6 with a 4.03 ERA in 19 Triple-A games in the Orioles system in 2013 after he underwent Tommy John surgery in 2012. He previously pitched nine seasons in Japan. The Cubs signed him to a minor league deal in December.
"He kept us off-balance," Pearce said. "He was throwing everything for a strike. He was working quick. He pitched really well today."
Arismendy Alcantara homered for the Cubs, who recorded their first series sweep since taking three straight at Boston from June 30 to July 2.
Hector Rondon struck out one in the ninth for his 21st save in 25 opportunities.
The AL East-leading Orioles finished their road swing 4-5 for their first losing trip this season.
Alcantara hit a one-out solo homer, his fourth of the season, to give the Cubs the lead in the fifth. The Cubs extended their advantage to 2-0 in the sixth on Anthony Rizzo's RBI double.
Wada struck out the side in the fourth and sixth innings. Of his 92 pitches, 59 were for strikes.
"He must have some very good deception, a little late life," Cubs manager Rick Renteria said. "The board might only read 89-90 (mph), but the way he gets the ball in his finish, seems to get by hitters a little with some quickness."
Miguel Gonzalez (6-7) allowed two runs and six hits in 6 1-3 innings after he was recalled from Triple-A Norfolk to replace Ubaldo Jimenez (4-9, 4.74 ERA) in the Orioles rotation.
Wada also had the game's first hit - and his first major league hit - on a two-out infield single in the third.
"I know it's not an easy world out here," Wada said. "I just kind of concentrate on that. Nothing's easy and I'm not taking anything for granted."
Orioles: 3B Manny Machado will undergo season-ending, right knee surgery on Wednesday in California. He is expected to rehab in Sarasota, Florida. ... To make room for Gonzalez, the Orioles designated INF Cord Phelps for assignment.
The Orioles begin a four-game series against visiting Tampa Bay on Monday. RHP Chris Tillman (10-5, 3.55) will start against Rays RHP Jake Odorizzi (9-10, 3.83).