Cristiano Ronaldo scored a hat trick in the space of 15 minutes to boost Portugal's hopes of qualifying for the World Cup with a 4-2 win at nine-man Northern Ireland, while Russia trounced Luxembourg 4-1 in Group F on Friday.
After Alexander Kokorin struck twice as Fabio Capello's Russia beat Luxembourg in Kazan to move provisionally to the top of the group. Portugal later restored its two-point lead as Ronaldo made the difference in an ill-tempered game that saw three red cards at Windsor Park.
But the Russians, who recovered from their surprise 1-0 defeat in Northern Ireland last month, have one game in hand and remain in a good position to qualify automatically for the finals in Brazil.
Portugal went into the match as favorites and Bruno Alves put the visitors ahead after 20 minutes. But West Bromwich Albion defender Gareth McAuley equalized with a fine header before Helder Postiga was sent off for an apparent headbutt in the 43rd minute.
Portugal stumbled when Jamie Ward gave the home team a 2-1 lead in the 52nd but left-back Chris Brunt received a red card at the hour-mark.
The dismissal lifted Portuguese spirits and Ronaldo leveled in the 68th, heading home a corner from Joao Moutinho. Left unmarked at the far post, Ronaldo doubled his tally with another header from close range and scored his 43rd international goal in the 83rd with a low free kick, minutes after Kyle Lafferty was sent off for a late challenge.
''I thought up until 60 minutes and Chris Brunt's sending off, we were the better team and in control of the game,'' Northern Ireland manager Michael O'Neill said. ''I thought they scored against the run of play and we responded well to that having gone into our shell a little bit. But then obviously the second sending off left us that man short and subsequently we weren't able to deal with that.''
In Kazan, a heavy downpour forced officials to delay the kickoff by an hour but the Russians did not waste time and scored inside 20 seconds when Kokorin lobbed Luxembourg goalkeeper Jonathan Joubert after collecting a pass from Alexander Kerzhakov.
Kokorin doubled his team's lead in the 35th minute with a header into the bottom-left corner. Kerzhakov and Alexander Samedov scored Russia's other goals and Aurelien Joachim pulled one back for Luxembourg.
Israel plays Azerbaijan on Saturday in the group's other match. Russia will next face Israel at home before finishing its qualifying campaign at Luxembourg and Azerbaijan while Portugal will host Israel and then Luxembourg in October.
The Czech Republic suffered a shock 2-1 loss to Armenia as Gevorg Ghazaryan struck in the closing moments for the visitors in Prague. Tomas Rosicky looked to have claimed a draw by cancelling out Karlen Mkrtchyan's opener but Ghazaryan's last-gasp effort kept Armenia's qualification hopes alive.
Denmark won 2-1 in Malta courtesy of a Leon Andreasen effort and a Ryan Camilleri own goal.
Sweden boosted their play-off hopes by claiming second spot in Group C outright after coming from behind to beat the Republic of Ireland 2-1 in Dublin. Johan Elmander and Anders Svensson were on target after Robbie Keane's 60th international goal had put the Irish ahead.
In the clash between the group's bottom two, a Kairat Nurdauletov penalty and an Andrey Finonchenko goal saw Kazakhstan come from behind to beat the Faroe Islands 2-1.
Group A leaders Belgium took another stride towards qualification with a 2-0 win over Scotland at Hampden Park. Steven Defour opened the scoring seven minutes before the break and Everton striker Kevin Mirallas made victory certain in the final minute.
Second-placed Croatia lost ground as they were held 1-1 by rivals Serbia in Belgrade. Mario Mandzukic put Croatia ahead after 53 minutes but Aleksandar Mitrovic responded 13 minutes later. Both sides ended with 10 men after Serbia's Nemanja Matic and Croatia's Josip Simunic were sent off.
Gareth Bale, who became the world's most expensive player by joining Real Madrid last weekend, stayed on the bench as Wales were beaten 2-1 in Macedonia in the other Group A game. An Aaron Ramsey penalty cancelled out Ivan Trickovski's early effort but Aleksandar Trajkovski won it in Skopje 10 minutes from time.
The Associated Press was used in this report.