Arsenal lost to Sunderland 2-0 in the fifth round of the FA Cup on Saturday, leaving the English Premier League club facing a seventh straight season without a trophy.
Arsenal is 17 points behind league leader Manchester City and lost the first leg of its Champions League knockout match 4-0 at AC Milan this week.
The Gunners failed to properly clear Sebastian Larsson's 40th-minute free kick and Richardson scored on a volley. Larsson then struck the post with 12 minutes left, with the rebound hitting Arsenal winger Alex Oxlade-Chamberlain and the ball rolling over the line for an own goal.
Thierry Henry — who scored the winning goal in last week's 2-1 Premier League win against the same opponent — was unavailable for Arsenal. He ended his loan from the New York Red Bulls on Thursday.
Chelsea drew 1-1 with Birmingham and must go to a replay, further threatening the job security of coach Andre Villas-Boas.
Villas-Boas acknowledged this week he had lost the support of some players after the club slipped to fifth in the league. His team was jeered at Stamford Bridge and needed a 62nd-minute goal from Daniel Sturridge to avoid a humiliating defeat.
"It was a quite poor result, of course," Villas-Boas said. "1-1 is not what we were expecting, but it gives us another chance at Birmingham to continue trying to win the trophy."
Second-tier Birmingham took the lead in the 20th when David Luiz and Branislav Ivanovic failed to clear a corner kick, giving David Murphy the chance to score from close range.
Second-tier Leicester eliminated Norwich with a 2-1 win at the Premier League club, Everton beat Blackpool 2-0, and Bolton won 2-0 at Millwall.
Everton was without Landon Donovan, who missed the final game of his loan from the Los Angeles Galaxy because of the flu. Everton went up 2-0 after just six minutes on goals by Royston Drenthe and Denis Stracqualursi.
Ryo Miyaichi and David Ngog scored for Bolton, which started U.S. defender Tim Ream for his debut.
In the second-tier League Championship, American forward Robbie Findley scored his first goal since Nov. 19 as relegation-threatened Nottingham Forest won 2-0 at home against Coventry. Findley's 86th-minute goal was his sixth of the season, including three in the league.
Robbie Rogers made his debut for second-tier Leeds with 12 minutes left but banged heads with an opponent and was carried off on a stretcher during injury time of his team's 3-2 win over Doncaster.
MILAN (AP) — Juventus regained the Serie A lead, rallying to beat Catania 3-1.
Pablo Barrientos put the visitors ahead in the fourth minute, but Andrea Pirlo tied it with a free kick in the 22nd minute. Catania's Marco Motta, loaned from Juventus in January, was ejected in the 65th for his second yellow, and Giorgio Chiellini put Juve in front in the 74th. Fabio Quagliarella added a goal in the 80th.
Unbeaten Juventus has 49 points, two more than defending champion AC Milan, which is at Cesena on Sunday. Milan hosts Juventus on Feb. 25.
MADRID (AP) — Cristiano Ronaldo put Real Madrid ahead his league-leading 28th goal, and the hosts went on to beat Racing Santander 4-0 to open a 13-point lead over second-place Barcelona in Spain.
Ronaldo's goal on a header in the sixth minute was his 35th for Real Madrid in all competitions this season.
Santander played a man short after Domingo Cisma was given a red card in the 39th minute for his second hand ball.
Karim Benzema added goals in the 45th and 89rd minutes, around a score by Angel di Maria, playing his first game since Dec. 17.
Barcelona hosts third-place Valencia on Sunday.
BRUSSELS, Belgium (AP) — American midfielder Mix Diskerud made his debut for Ghent, starting in a 1-1 tie at Lokeren.
Diskerud, obtained on loan from Norway's Stabaek last month, is to report to the U.S. under-23 team training camp on Feb. 26 ahead of an exhibition against Mexico three days later. The Americans are in Olympic qualifying next month.
FRANKFURT, Germany (AP) — Borussia Dortmund won 1-0 at Hertha Berlin to stretch its unbeaten streak to a club-record 16 games and stay in first place in the Bundesliga.
Kevin Grosskreutz scored on an overhead volley in the 66th minute for the defending champion, which lost to Hertha at home in the first half of the season but has now won six straight.
Dortmund was without injured Japan midfielder Shinji Kagawa in Berlin's Olympic stadium and had to work hard against a team playing its 1,000th Bundesliga match.
Borussia Moenchengladbach also won on the road, beating Kaiserslautern 2-1 on early goals by Patrick Herrmann and Juan Arango to stay in the top three. It was Moenchengladbach's first win at Kaiserslautern since 1995.
Powerhouse Bayern Munich fell to third place with a 0-0 draw at last-place Freiburg. Werder Bremen won 3-1 at Hamburger SV; Nuremberg edged Cologne 2-1 with American Timmy Chandler pushed up to midfield; and Bayer Leverkusen beat Augsburg 4-1.
GLASGOW, Scotland (AP) — Rangers' troubles deepened with a 1-0 Scottish Premier League defeat against Kilmarnock and the loss of its unbeaten home record.
Four days after the 140-year-old Glasgow club was deducted 10 points for seeking bankruptcy protection, Rangers lost on a 12th-minute goal by Dean Shiels.
Defender Sasa Papac was sent off for the defending champions, whose first loss in 14 matches at Ibrox also ended a run of eight straight home wins over Kilmarnock.
Rangers are 14 points behind leader Celtic, which is at Hibernian on Sunday. The 54-time Scottish champions have almost no chance of successfully defending their title.
PARIS (AP) — Defending champion Lille made up ground in the title race and consolidated third place by edging Lorient 1-0 on Mathieu Debuchy's goal off a cross from Benoit Pedretti in the 76th minute.
Lille is eight points behind Ligue 1 leader Paris Saint-Germain, which hosts second-place Montpellier on Sunday.
Marseille extended its unbeaten streak in all competitions to 15 games but lost ground in the chase for a Champions League spot by drawing 1-1 with Valenciennes.
Marseille's Alou Diarra headed home a cross from Rod Fanni in the 16th, but Gil tied it from close range in the 51st.
Also, it was Nancy 0, Toulouse 3; Ajaccio 0, Brest 0; Caen 2, Evian 2; Dijon 3, Nice 0; Sochaux 0, Auxerre 0.
ATHENS, Greece (AP) — Simao and Haris Mavrias scored their first goals in the Greek league early in the second half to give leader Panathinaikos a 2-0 victory over host Ergotelis 2-0.
Simao opened the scoring in the 55th minute and Mavrias followed four minutes later.
The win left Panathinaikos five points ahead of archrival and defending champion Olympiakos, which plays Panionios at home Sunday.