PHOENIX -- The Astros allowed only four runs during this week’s two-game series against the D-backs. Yet, that didn’t lead to a sweep in their brief trip to Chase Field.

Houston fell, 3-2, in 10 innings in Wednesday afternoon's finale, as closer Ryan Pressly yielded a walk-off sacrifice fly to Ketel Marte. The Astros split the set after previously taking three of four against the Angels in Anaheim to open the season.

“We have won four out of six, I think that’s a good start for us,” Houston second baseman Jose Altuve said. “We’re going to keep playing game by game and hopefully we keep winning some games.”

As the Astros head to Seattle for a three-game weekend series, here are three takeaways from their quick swing through the desert.

The pitching has been an early backbone
Through the first six games, Houston pitchers lead MLB with a 1.69 ERA, having allowed only 10 earned runs in 53 1/3 innings. The Astros have given up three or fewer runs in all but one contest so far (Friday’s 13-6 win over the Halos).

After a shortened Spring Training, Houston manager Dusty Baker isn’t surprised that opposing hitters are having trouble against his team’s pitching staff, as he believes they’re struggling with timing early in the year.

“Right now, pitchers as a whole have an advantage,” Baker said. “The good thing for them and us is that these are confidence builders. You build confidence one block at a time, and then, hopefully we build a castle at the end.”

A strong foundation has been laid by the Astros’ hurlers, for sure. Even though Framber Valdez went only three innings and issued five walks Wednesday, he held the D-backs to one run. Houston’s rotation has a 1.63 ERA, and no starter has allowed more than two runs.

Valdez limited damage a day after Luis Garcia threw four scoreless innings in his first start of the season. The other encouraging development to come from Chase Field this week was that Lance McCullers Jr. (out with a right flexor strain) began his throwing program, which he’s scheduled to continue Friday in Seattle.

As starters get more stretched, as well as once McCullers returns, the Astros’ pitching may only get better and could lead them to greater success in 2022.

Javier continues to show value out of ’pen
After Valdez’s short start, Houston’s first four relievers combined for six scoreless innings. The most impressive performance among that group came from right-hander Cristian Javier, who struck out five over three hitless frames.

Over his first three big league seasons, Javier has made 19 starts and 31 relief appearances. He could eventually join the rotation this year if the need arises, but he’s continuing to prove how valuable he can be as a multi-inning reliever.

“I think it’s something that as a team we need, especially when we have an outing like today where maybe one of us doesn’t have a great start,” Valdez said.

Last year, Javier posted a 3.38 ERA over six postseason relief outings, not allowing a run until Game 4 of the World Series. This season, he has fanned eight in 4 2/3 scoreless frames over his first two appearances, and he should continue to pitch important innings for the Astros moving forward.

Altuve breaks through for 2
Entering Wednesday, Altuve was 1-for-15 with five strikeouts to open the season. But that wasn’t a concern for Baker.

“I don’t worry about Jose,” Baker said. “I think Jose worries about Jose more than we worry about Jose.”

Baker believes Altuve will get going, and Wednesday’s game may have been the start. The second baseman collected a pair of singles -- two of the three hits allowed by D-backs starter Merrill Kelly -- and stole his second base of the season.

Altuve nearly homered with runners on second and third and no outs in the 10th, sending a 2-2 fastball from righty Noé Ramirez deep over Arizona’s bullpen. However, it hooked just foul past the left-field foul pole, and Altuve struck out on the next pitch to finish his 2-for-5 day.

The Astros scored only one run in the 10th, before the D-backs rallied for two in the bottom of the inning. And although Houston tallied only four runs in the series, Altuve isn’t concerned.

“We’re not worried at all,” Altuve said. “We have good players that are here, we’re good.”

Altuve is among that group, and his bat may just be starting to heat up, which would be a big boost for the Astros.