Club America struck early and held on at the end to beat Santos on Sunday and claim the final available berth in the Mexican Primera Division's "Bicentenario" playoffs.
Morelia and Pachuca also clinched playoff berths on the final weekend of the spring Clausura season, and American forward Herculez Gomez shared the scoring title.
Angel Eduardo Reyna's team-best sixth goal of the spring Clausura season, an eighth-minute strike, and a huge save by goalkeeper Armando Navarrete in the 86th minute sent America to a 1-0 triumph Sunday over Santos at Estadio Azteca, knocking their Mexico City rival Cruz Azul out of contention.
The quarterfinals will begin with first-leg matches next weekend.
America qualifies: The Aguilas needed some help to be in position to qualify, and they got it Saturday when hated rival Guadalajara rallied to tie Cruz Azul, 1-1, Atlas was held to a 1-1 draw by Jaguares, and Morelia managed only a 1-1 draw at home against Monterrey.
Fernando Lopez of Club America jumps in the air in a battle for the ball with Fernando Arce of Santos Laguna on Sunday. Club America got the help it needed to reach the Mexican league playoffs.
America, which claimed the No. 6 seed and will meet third-seeded Toluca in the quarterfinals, would have been eliminated had Cruz Azul, Atlas and Morelia won.
Morelia nonetheless qualified, and Pachuca got through as Edgar Benitez converted two penalty kicks in a 2-1 triumph at UANL Tigres.
Cruz Azul's downfall was an Edcarlos Conceicao own goal in the 78th minute, the first tally for Chivas in four games and only its second since March 27. Guadalajara took the biggest hit, losing five top players, when Mexico's national team opened its pre-World Cup camp earlier this month.
'Liguilla' openers: Apertura champion Monterrey secured the top seed for the Clausura playoffs a week ago, and the Rayados, who meet Pachuca in the quarterfinals, head into the postseason with a 15-game unbeaten streak. Three of their last four, four of last six and five of their last eight outings have been 1-1 draws; their only loss this season was a 3-0 decision to Atlas on Jan. 23.
No. 2 seed Guadalajara, which will face Morelia, is reeling as the playoffs begin. Chivas is 2-5-2 since an 8-0-0 start, and it's winless in its past four games.
Fourth-seeded Pumas UNAM, which has the Primera Division's stingiest defense, allowing just 10 goals in 17 games, will meet Santos. First legs will be played next weekend, with second legs scheduled for May 8 and 9.
Top scorer: Puebla's Herculez Gomez, who was born in L.A. and raised in Las Vegas, shared the Bicentenario scoring title with Guadalajara's Javier "Chicharito" Hernandez and Atlante's Johan Fano.
Gomez, who left the Kansas City Wizards to sign with Puebla just after New Year's, was missed Los Camoteros' 2-1 loss to Toluca on Sunday, suspended for yellow-card accumulation. Hernandez, who scored his 10 goals in 11 games, hasn't played for Chivas since Mexico's pre-World Cup camp opened.
Gomez scored 24 goals in 129 Major League Soccer games with the Galaxy, Colorado and Kansas City. He scored 12 goals (18 in all competitions) and was team MVP when L.A. won the MLS Cup title in 2005.
This week's results (home teams listed first)
Estudiantes Tecos 3 (Medina 43, og Fano 54, R. Ruiz 67), Atlante 2 (Medina 43, Amione 90)
Toluca 2 (A. Gonzalez 9, Mancilla 17), Puebla 1 (Zinha 6) Indios de Ciudad Juarez 2 (Gimenez 17, 27), Pumas UNAM 0 America 1 (Reyna 8), Santos 0
Group 1: Guadalajara 32 points, Toluca 30, Atlas 25, Gallos Blancos 21, Indios 15, San Luis 14.
Group 2: Monterrey 36, Morelia 25, Pachuca 25, America 22, Puebla 19, Jaguares 18.
Group 3: Pumas UNAM 28, Santos 28, Cruz Azul 25, Estudiantes Tecos 19, UANL Tigres 19, Atlante 16.
This week's games
Quarterfinals, First Legs Saturday
Monterrey at Pachuca, 3 p.m.
Guadalajara at Morelia, 5 p.m.
Toluca at America, 3 p.m.
Pumas UNAM at Santos, 5 p.m.
Second Legs: May 8 and 9
1. Herculez Gomez (Puebla) 10
Johan Fano (Atlante) 10
Javier Hernandez (Guadalajara) 10
4. Jackson Martinez (Jaguares) 9
5. Raul Mancilla (Toluca) 8
6. Fredy Bareiro (Estudiantes Tecos) 7
Dario Carreņo (Monterrey) 7
Miguel Sabah (Morelia) 7
Miguel Zepeda (Atlas) 7
Alvaro Gonzalez (Puebla) 6
Angel Eduardo Reyna (America) 6
Orange County native Scott French has been writing about soccer for more than 30 years for dozens of publications and Web sites. He was senior editor at Soccer America and was managing editor of MajorSoccerLeague Magazine from April 2007 until last summer. He has covered three World Cups for the Long Beach Press-Telegram and Los Angeles Daily News, two Women's World Cups for Soccer America, the Olympic Games, European Championship, U-20 World Cup, eight MLS Cups and all four professional women's championship games.