"As a baseball player I'm happy to have such good facilities and environment to work out in," Darvish told a news conference after throwing 19 pitches in a five-minute loosen-up.
"It just felt really good," added the 25-year-old, who apparently is already picking up locker-room English from his new team mates.
"They are helping me and teaching me English. It might not be formal English but they're teaching me."
Even instructed to throw at 80 percent power, Darvish, who last month signed a six-year contract worth $60 million with the Major League club, impressed coaching staff and players alike.
"You could tell he has good command," Japan's Kyodo news agency quoted Rangers catcher Mike Napoli as saying. "I caught a slider, curveball, fastball, two-seamer to both sides, a splitter. I was impressed."
As more than a 100 reporters, many from Japan, tripped over themselves trying to follow Darvish's every move, Texas pitching coach Mike Maddux likened it to "post-season pandemonium."
Rangers manager Ron Washington stressed the need for Darvish not to over-exert at spring training or put added pressure on himself.
"We certainly don't want him to overwork himself," said Washington. "He's a smart guy. He'll do whatever he has to do to help us move forward."
The 6ft-5in (1.96m) right-hander left Japan's Nippon Ham Fighters with a 93-38 career record and is widely regarded as Japan's best pitcher.
(Reporting by Alastair Himmer in Tokyo; Editing by John O'Brien)