LONDON — Theo Walcott’s first-half goals and Alexis Sanchez’s boundless energy helped Arsenal to a straightforward 2-0 win over Basel in the Champions League on Wednesday.

Walcott opened the scoring in the seventh minute when a long ball over the top found Sanchez, who ran down the left before crossing into the box. An unmarked Walcott darted behind the defense to power a header beyond the reach of Basel goalkeeper Tomas Vaclik.

Walcott’s second goal came from a clinical one-two with Sanchez, whose back was to goal when he released the England international with a flicked pass. Walcott rifled home the return ball off the post in the 26th.

The result leaves Arsenal fighting for top of Group A with Paris Saint Germain. Both teams have four points after two matches, following PSG’s 3-1 victory at Ludogorets on Wednesday.

“I would like to congratulate my team for the quality that they produced tonight,” Arsenal manager Arsene Wenger said. “But my only regret is that we didn’t take enough of the chances that we created. But it’s a good basis to have a taste for more.”

Arsenal found cracks in Basel’s defense throughout the match at Emirates Stadium, and the home side could have easily had half a dozen goals by the break — if not for wayward finishing and some excellent saves from Vaclik.

The first half virtually mirrored Arsenal’s dominant display against Chelsea in the Premier League on Saturday, when the Gunners scored all of its goals before halftime in a 3-0 win.

“I think it was a game where again the first half was top quality,” Wenger said. “The pace, the quality of our movement, the technical quality. And we created many dangerous situations.”

Much of Arsenal’s dazzling play came from Sanchez’s vision and industry, with the forward’s pace and trickery too much for Basel to handle at times as his link-up play with Walcott paid dividends.

Wenger has persisted with playing Sanchez as a lone striker, a decision which initially appeared to backfire at the start of Premier League season. But now, the Chilean is finding his form.

“I think at the moment, yes,” Wenger said. “He looks like he has the ingredients to do very well there, and he’s getting stronger in every single game.”

The visitors came back into the match for brief spells in the second half, most notably when midfielder Birkir Bjarnason smashed a shot that forced Arsenal goalkeeper David Ospina to palm the ball over the crossbar.

Basel coach Urs Fischer used a new tactical system, playing three defenders at the back. It was a bold move taken at a time when Basel has dominated the Swiss league with nine straight wins.

“The intention was to not give Arsenal so much space, the space that they want,” Fischer said. “The system actually worked at times …we also had phases where we lacked courage to defend high.”

Basel faces PSG in its next group match, and the Swiss side needs to pick up points to have a chance of advancing.

“I believe that today we saw our limitations,” Fischer said. “It’s good to see that. Now we have to learn. We have to benefit from that.

“We’re lacking points and we now have to try to change that in Paris.”

Arsenal was forced to wear its yellow-and-blue away kit at Emirates Stadium after UEFA said that both of Basel’s strips would clash with the home team’s red-and-white colors.

Arsenal midfielder Granit Xhaka faced his older brother Taulant Xhaka for the time since the siblings lined up against each other at the European Championship in June — Granit for Switzerland and Taulant for Albania.