The second half of Stargate Atlantis‘s mid-season two-parter was the most-watched of the season so far, executive producer Joseph Mallozzi reported on his blog. “The Lost Tribe” earned a 1.5 average household rating last Friday.

This is a huge increase of four-tenths of a point (36 percent) from part one, “First Contact,” which faced stiff competition from the first U.S. presidential debate on September 26. It also tops the previous season-high, the 1.3 rating earned by “Search and Rescue,” “The Daedalus Variations,” and “The Queen.”

It was also Atlantis‘s first episode this season in the 9 p.m. time slot.

“I think [the rating] says a lot about the quality of the show as well as its legion of loyal fans,” Mallozzi said. “I mean, if you think about it, it’s a pretty incredible achievement. A series typically sheds viewers the longer it stays on the air but here we are, completing work on our fifth (and final) season, and we’re pulling in better numbers than ever. So a big thanks and congratulations to everyone who worked so hard to make this season the most successful season of Stargate Atlantis in years.”

The episode guest starred Stargate SG-1‘s Michael Shanks as Daniel Jackson, who visits Atlantis in hopes of finding a hidden Ancient laboratory. When a previously unknown enemy shows up and kidnaps Jackson and Rodney McKay, they make a shocking discovery about the aggressive species’ identity.

The SCI FI Channel is expected to confirm this rating, and how Atlantis ranked for the week, in a couple of weeks.

Don’t miss “Outsiders” this Friday at Atlantis‘s new time, 9 p.m. Eastern and Pacific (8 Central) on SCI FI.