(CNN) -- Senegal's Demba Ba scored twice on a dream debut as English FA Cup holders Chelsea won 5-1 at Southampton in their third round tie Saturday.
Ba was one of the first big signings of the January transfer window and immediately proved his worth after his new side had fallen behind to their English Premier League (EPL) counterparts through an early Jay Rodriguez goal at St Mary's.
He equalized as he touched home Juan Mata's shot before Victor Moses made it 2-1 and Branislav Ivanovic headed a third.
Ba's second and his team's fourth after an Eden Hazard assist sealed victory, which was rounded off by a penalty from Frank Lampard late on.
The FA Cup is football's oldest cup competition, dating back to 1871, and Chelsea have a superb recent record in the competition, winning four of the last six stagings, including a 2-1 win over Liverpool at Wembley to lift the famous trophy last year.
Interim manager Rafa Benitez, criticized for resting key players as they lost 1-0- to QPR in midweek, was delighted Ba led the way as they got back on track.
"It is always important for a striker to score goals, but more than just the goals was his contribution for the team," Benitez told ITV Sport.
Ba's former side Newcastle United became the first high profile team to exit a competition famous for upsets.
They were beaten 2-0 at second flight Brighton, who had also put them out last year.
Goals in each half from Andrea Orlandi and Will Hoskins put the skids under Alan Pardew's men, who have slipped alarmingly down the EPL in recent weeks and have a lengthy injury list.
A sorry afternoon was rounded off when striker and captain Shola Ameobi was sent off for a second yellow card.
The other big upsets saw non-league Luton put out second flight Wolves, while Cardiff, who look set for promotion to the EPL, were beaten 2-1 by lowly Macclesfield.
EPL leaders Manchester United, the record 11 time winners of the competition, were also close to going out at West Ham in the late kick off.
They trailed 2-1 at Upton Park after a pair of headed goals by James Collins, but the prolific Robin van Persie, on as a late substitute, equalized in injury time.
The Dutchman converted after a superb crossfield pass from veteran Ryan Giggs. Tom Cleverley put United ahead in the 23rd minute, but new Hammers signing Joe Cole provided two fine crosses for Collins to give the home side the lead.
Tottenham Hotspur, among the favorites for the competition, thrashed third flight Coventry 3-0 at White Hart Lane.
Spurs were shocked by Coventry in a famous 1987 final, but there was to be no repeat as United States international Clint Dempsey scored twice in the first half.
Gareth Bale, returning after suspension, grabbed the other to confirm his fine form for the side managed by former Porto and Chelsea boss Andre Villas-Boas.
EPL champions Manchester City also eased through with a 3-0 home win over Watford.
Mario Balotelli, under the spotlight after his training ground tussle with manager Roberto Mancini, came off the bench to set up the third for Marcos Lopes.
In Spain, La Liga resumed after a Christmas break and Deportivo La Coruna made a great start under new coach Domingos Paciencia with a 1-0 win over fourth-placed Malaga.
A second-half Luis Pizzi strike took the off the bottom of the standings. Leaders Barcelona are in action Sunday.
In Serie A, Lazio cut the gap on leaders Juventus to five points with a dramatic 2-1 win over nine-man Cagliari.
Abdoulay Konko's 79th minute strike equalized Marco Sau's opener for Cagliari before a late penalty from Antonio Candreva sealed the three points.
Cagliari had goalkeeper Michael Agazzi and midfielder Andrea Cossu sent off in the penalty incident.