LONDON (AP) ― Demba Ba scored twice in his debut as Chelsea got off to a perfect start in its FA Cup defense with a 5-1 rout of Southampton in the third round, while Robin van Persie scored an injury-time tying goal for Manchester United to tie 2-2 at West Ham and earn a replay.

A day after completing his move from Newcastle, Ba took just 35 minutes Saturday to score at Southampton to tie the score 1-1 after Jay Rodriguez scored.

After two more Chelsea goals from Victor Moses and Branislav Ivanovic, Ba scored his second before Frank Lampard wrapped up the rout.

“It is always important for a striker to score goals but more than just the goals it is the contribution for the team,” Chelsea manager Rafa Benitez said.

Newcastle struggled without Ba, however, and was the only English Premier League team to be ousted by lower-league opposition, falling 2-0 at second-tier club Brighton.

At West Ham, Joe Cole set up two nearly identical goals for James Collins as the Hammers looked to knock off United. But Van Persie came on as a substitute to salvage a tie.

Manchester City had no trouble ousting Watford 3-0, while Aston Villa had to come from behind to oust another League Championship club, Ipswich, 2-1.

In a rematch of the 1987 final, Coventry was on the losing end this time as Tottenham won 3-0. American Clint Dempsey scored twice.

The biggest upsets came from fifth-tier nonleague teams defeating second-tier opposition. Macclesfield beat League Championship leader Cardiff 2-1, and Luton defeated Wolverhampton Wanderers 1-0.