CBS was breathing a small sigh of relief on Wednesday as Atlanta’s thrilling win over Pittsburgh swept a higher-profile team into the World Series with by far the best numbers for any playoff game this year.

Even so, the web has cause for concern, as Atlanta–known as “America’s team” for its national exposure on TBS–goes up against Toronto, the first Canadian club ever to play in the Fall Classic.

“I don’t think it’s going to help” having Toronto in the Series, said Paul Schulman, head of ad agency the Paul Schulman Co., adding that time-buyers “couldn’t care less” about what sort of numbers the games attract north of the border.

Networks can usually count on 60-plus shares in host cities of the Series and in that sense caught a break with Atlanta edging Pittsburgh, which is not only a larger market (10th nationally vs. 17th) but enjoys broad fan support throughout the South.

Still, having Toronto as the opponent may offset some of those gains, and Schulman speculates that the first couple of games (tomorrow and Sunday) may suffer in the ratings until the contest starts to define how it will play out.

A network spokeswoman maintained that several factors will mitigate against any potential ratings loss due to a Canadian team being in the Series, including Toronto’s high profile from having been in the playoffs the last several years and the team’s marquee ballplayers.

CBS benefited from a terrific seven-game World Series last year between Atlanta and Minnesota that culminated with a monster 32.2 rating, 49 share in the Nielsens for the deciding seventh game.

The two highest-rated series of the last 10 years have both involved teams from New York, the nation’s largest market, once in 1981 against the Dodgers (the second-largest market) and again in ’86 vs. Boston.

The network finished this year’s eight prime time playoff games with a 12.6/ 22 average, down 9% from the 13.8/24 the web slugged out last year. Wednesday’s nail-biter pulled a strong 18.2/31, off 8% from Game Seven of the National League Championship Series last year.

CBS said it was sold out for Game Seven and expected to do well with sales on the World Series, which will include ad buys by all three presidential campaigns. The top asking price was reportedly $ 300,000 per 30-second spot, although the web will charge a lower rate to the campaigns.

CBS also sold more time within the Series this season during its upfront sales, holding back less inventory. Last year’s Series averaged a 23.9 rating, and even with the Blue Jays in the Series observers note that smaller markets have drawn well in the past, such as ’85 series pitting Kansas City against St. Louis.

“You never really know,” Schulman said. “An awful lot has to do with how good the games are.”

The way the games are deployed should give CBS easy Nielsen victories the next two weeks. After Games One and Two, which will be included in this week’s average, all five possible subsequent games would air next week.

CBS averaged a 15.7/26 in prime time Wednesday, while NBC and ABC shot it out for second with a 12.4/20 and 12.3/20, respectively. ABC ranked second among adults 18-49, however, and saw new sitcom “Laurie Hill” (13.1/21) build for the second consecutive week, though it did fall 30% off its “Home Improvement” lead-in.

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