D.C. United, Seattle seek foothold as CCL quarters kick off

There is no room for error as the CONCACAF Champions League quarterfinals commence on Tuesday. The stakes are high with four MLS teams set to face four Liga MX clubs at this stage for the first time in the Champions League era. And the eight involved teams know it.

D.C. United and Seattle Sounders face the most immediate tasks as they open their quarterfinal ties. They must grapple with different tasks, but they share a common objective. Their potential path to the semifinals kicks off in earnest tonight.

Querétaro -- D.C. United (live, 8:00p.m. ET, FS1, FOX Sports GO, FOX Soccer 2Go)

Quéretaro manager Victor Manuel Vucetich knows how to win in this competition. Gallos Blancos hope to lean on Vucetich's experience to navigate through this opening leg at RFK Stadium and set the side on course for the semifinals.

Recent form offers some cause for concern ahead of the home leg at Estadio Corregidora, though. Querétaro enter this match after a creditable 2-2 draw against Tigres UANL, but they also nurse some genuine defensive concerns after conceding seven times in the past four matches.

Part of those problems arose from the opposition (including Cruz Azul and Tigres), but Gallos Blancos' desire to play directly influences matters, too. Balance is the key for Vucetich and his players considering the lack of creativity in the side (seasoned playmaker Sinha still features regularly) and the need to assert control in possession against a United side expected to sit deeply. The impending return of Emanuel Villa from injury offers a boost, but Luis Gil is cup-tied after playing for Real Salt Lake in group play.

United entered the offseason with a dire need to improve its work on the ball. The arrival of Luciano Acosta from Boca Juniors provides an instant boost in terms of creativity and precision on the ball, but Ben Olsen's side remains an outfit poised to disrupt the opposition and play quickly toward Fabian Espindola up front. There are a couple of other tweaks to watch (Nick DeLeon might slide inside, for example), but United must rely on defiance and grit as usual to grind out a result. The success of this task hinges on the counter and the willingness to soak up pressure to conserve energy at altitude (elevation: approximately 6,000 feet).

Seattle Sounders host Club América without departed forward Obafemi Martins. The veteran striker is expected to complete a move to Shanghai Shenhua in the next few days.

Seattle Sounders -- Club América (live, 10:00p.m. ET, FS1, FOX Sports GO, FOX Soccer 2Go)

The marquee tie in this quarterfinal round opens at CenturyLink Field with the defending champions paired against one of the largest clubs in MLS. Most of the pressure here falls squarely on the Sounders to produce a good result and secure a foothold ahead of the return trip to Estadio Azteca next week.

Seattle must accomplish the feat in the midst of transition. Sounders boss Sigi Schmid opted to overhaul the tactical setup during the preseason and shift his side to a 4-3-3 formation. The switch highlights the strength up front with Clint Dempsey, Jordan Morris and Nelson Valdez to lead the line, but it also creates tracking concerns in the wide areas. This affair presents the first opportunity to see how the revamped side works in a competitive match.

"It's going to be a big game for us against Club América, but we are at home," Seattle midfielder Osvaldo Alonso told reporters on Monday. "We have to get a good result to go there and advance to the next round."

América continue to wind through the Clausura without providing manager Nacho Ambriz with any measure of security. Oribe Peralta once again looms as the influential touchstone up front, while Las Aguilas' adroit work in possession paves the way to assert control in the proceedings.

Ambriz must cope with a handful of absences after leaving Dario Benedetto, Moises Munoz and William da Silva back in Mexico City to rest after the wild 3-3 draw with Cruz Azul on Saturday. Recent signing Cuauhtemoc Blanco -- rather sensationally registered for Liga MX play ahead of a possible cameo against Morelia this weekend -- isn't available to feature, either.