LONDON: Chelsea midfielder Frank Lampard won't take any pleasure from plunging West Ham deeper into relegation trouble even though the former Hammers star faces another hostile reception at Upton Park on Sunday.

Lampard has been public enemy number one in east London since quitting West Ham to join bitter rivals Chelsea for 11 million pounds (12.3 million euros) in 2001.

The 31-year-old, who spent nine years at West Ham, has suffered vicious abuse from the Hammers fans every time he has faced his old club and he knows it will be no different this weekend.

But despite all the taunts, Lampard is sad to see the Hammers languishing second bottom of the Premier League because of former Chelsea favourites Gianfranco Zola and Steve Clarke - now manager and assistant at West Ham - who worked with the England international at Stamford Bridge.

"I have a lot of respect for Gianfranco and Steve Clarke. It's been difficult for them. They have a lot of financial difficulties and have had to sell a lot of players," Lampard said.

"I don't want to see them do badly at all. They're great lads. It's difficult, but then it's a difficult league."

While Lampard would genuinely like to see West Ham prosper, he will show no compassion on Sunday as Chelsea bid to cement their position as league leaders going into the busy Christmas programme.

By the time Chelsea kick off on Sunday, they could be ahead of Manchester United only on goal difference if the reigning champions win at Fulham 24 hours earlier.

After recording a string of convincing victories last month, Carlo Ancelotti's side have spluttered of late.

They won for the first time in five matches against Portsmouth on Wednesday, but their victory against the league's bottom club was less than convincing.

The Blues have conceded 11 goals in five games and looked nervous at the back again against Portsmouth.

Yet Lampard is adamant his side are still on course to win the title and he expects them to rediscover their dominant form soon.

"I'm sure people would have been talking again if we hadn't beaten Portsmouth, but that's why it was important to win," he said.

"We're having a patch at the moment where we're not pulling away from teams when we might do and every free-kick and corner seems to drop to them in a funny way. We are being punished every time and it is just a phase we're in.

"We went a long time without conceding goals, and that was fantastic, but now we're having a patch where we are.

"It's important we just keep going. We're three points clear at the top and we need to pick up wins. I think we can move on and put this all behind us."

Chelsea's hopes of a second successive win will be boosted by Didier Drogba's return to action after the Ivory Coast striker missed the Portsmouth win with a back problem.

West Ham welcome back Matthew Upson from a hamstring injury, but will be without Carlton Cole, Valon Behrami, Zavon Hines and Kieron Dyer.

Those injuries have only added to the gloom around Upton Park after three consecutive defeats.

The tame manner of the loss at Bolton in midweek was especially worrying for Zola, but the Italian has no intention of changing his purist principles.

Zola, who played for Chelsea from 1996 to 2003 after being sold by Ancelotti when he was in charge at Parma, said: "The last two games were painful, but this is the situation. They belong to the past and if you keep switching your mind to the past, it doesn't help.

"At West Ham, they want to play football in a certain way. They're not interested in playing differently, and that's why I was appointed and what I try to do.

"I try to keep that plan and to get results as well. I don't see why you shouldn't play good football and get results as well."