Canada's upset of No. 1 Spain in the first round of the 2013 Davis Cup opened a path to the championship round for the winner of this week's tie at Taco Bell Arena.
No. 4 Serbia and the No. 6 United States team are the highest-ranked nations left in the top half of the bracket. They meet Friday through Sunday in Boise.
The lower half of the bracket, on the other hand, is loaded with Nos. 2 (defending champion Czech Republic), 3 (Argentina), 5 (France) and 7 (Kazakhstan).
Spain, winner of the 2000, 2004, 2008, 2009 and 2011 events and the runner-up last year, lost 3-2 to Canada without its top two singles players, including Rafael Nadal.
"Not seeing Spain in there is the biggest surprise," U.S. captain Jim Courier said. "They have been the dominant nation in the past 15 years."
Here's a look at this week's four quarterfinal matchups. The winners meet Sept. 13-15 and the championship round is Nov. 15-17.
If the U.S. wins, it would face Canada at home or travel to Italy for the semifinals.
NO. 4 SERBIA AT NO. 6 U.S.
Top players: No. 1 Novak Djokovic (Serbia), No. 20 Sam Querrey (U.S.), No. 1 doubles Bob and Mike Bryan (U.S.)
The matchup: The U.S. will have the higher-ranked player/team in three of five matches. However, Querrey and John Isner are 4-12 against Serbia's singles players.
NO. 9 ITALY AT NO. 8 CANADA
Site: Vancouver, B.C.
Top players: No. 16 Milos Raonic (Canada), No. 5 doubles Daniel Nestor (Canada), No. 19 Andreas Seppi (Italy)
The matchup: Canada, a first-time quarterfinalist, likely will need to win the doubles match to prevail and possibly create the first showdown with the U.S. since 1965.
NO. 5 FRANCE AT NO. 3 ARGENTINA
Site: Buenos Aires, Argentina
Top players: No. 8 Jo-Wilfried Tsonga (France), No. 10 Richard Gasquet (France), No. 14 Juan Monaco (Argentina)
The matchup: France has a clear edge with two top-10 singles players and an Olympic medalist doubles team. Plus, Argentina is missing its best player - No. 7 Juan Martin Del Potro. Home-court advantage might not be enough to compensate.
NO. 2 CZECH REPUBLIC AT NO. 7 KAZAKHSTAN
Site: Astana, Kazakhstan
Top players: No. 6 Tomas Berdych (Czech Republic), No. 43 Radek Stepanek (Czech Republic)
The matchup: Kazakhstan upset Austria's best player twice to advance to the quarterfinals. They'll be significant underdogs in this tie - but they're at home and they upset the Czechs two years ago on the road.
Chadd Cripe: 377-6398, Twitter: @IDS_BroncoBeat