He will have to settle for a share of the major-league home run lead with teammate Alfonso Soriano and three other players.
"Sori's pretty familiar with the top of the leaderboard," Teixeira said. "It's only my third year. To be able to be up with him and guys like A-Rod, it's nice right now."
Ricardo Rodriguez (2-0) has won both of his starts since taking over in the rotation for Ryan Drese, the opening day starter who was claimed off waivers by Washington last week after being designated for assignment by the Rangers.
Rodriguez pitched into the eighth, allowing three runs and six hits with no walks.
"When you get some runs early, it makes you more confident," Rodriguez said. "You can throw strikes. They had to swing the bats."
With a pair of two-run homers, Teixeira had his third multihomer game this season and seventh of his career.
Teixeira and Soriano both have 19 homers, matching Alex Rodriguez, Miguel Tejada and Andruw Jones for tops in the majors.
"It's surprising to have two on the same team," said Soriano, traded to Texas from the New York Yankees for Rodriguez before the 2003 season. "It's not competition. When we're both hitting, it's better for the team."
They sure looked like they were competing in the first inning.
Teixeira's first homer caromed off the right-field foul pole to put the Rangers ahead to stay and match Soriano for the team lead. But one out later, on a 3-0 pitch, Soriano hit a ball deep into the left-field stands to take over again and reach the major league lead.
Laynce Nix drew a leadoff walk in the second and Matthews followed with his second homer. Teixeira 19th homer in the same inning went to left to make it 7-0, and he later had a double.
"All four home runs came on offspeed pitches that were up," said Armas (3-4), who had allowed just five homers over 41 2/3 innings his first seven starts. "It's tough to make a mistake, especially in the ballpark where the ball flies."
Ryan Church homered twice and Cristian Guzman also connected for Washington, which has lost consecutive games and three of five since winning 10 in a row. Guzman's two-run shot with none out in the eighth, his second in two games and third this season, ended Rodriguez's night.
The three-game series between the new and old Washington teams wraps up Sunday. The Rangers were the expansion Washington Senators from 1961-71, and the last team to play in the nation's capital until the Montreal Expos moved there this season.
"We were out of this game before it got started," manager Frank Robinson said. "I don't want to be swept."
Rodriguez was 3-1 with a 2.03 ERA in five starts last season for Texas before his right elbow was fractured by a line drive on July 22. He went 7-3 with a 2.91 ERA in 12 games for Triple-A Oklahoma to start this season.
Though he didn't give up another run after the early outburst, Armas yielded seven runs and seven hits in five innings. He threw two wild pitches and walked four.
- The Rangers have 210 home runs in interleague history, most in the major leagues.
- Armas has lost six straight decisions over his last 10 road starts since April 10, 2003.
- Rangers SS Michael Young was 2-for-5, his fourth straight multihit game. He is hitting .413 (52-of-126) over his last 30 games, raising his season average from .243 to .321.
- Teixeira also made an impressive defensive play, backhanding a short-hop grounder and then beating Guzman to first base for the final out of the fifth.
- It was Church's first career multihomer game.