Piquionne, 31, who spent last season playing for the new Hammers boss while on loan at Portsmouth, has joined for an undisclosed fee from Lyon on a three-year deal.

Barrera, meanwhile, arrives in a £4million deal from Pumas, after the 23-year-old received his work permit yesterday.

Following the capture of German midfielder Thomas Hitzlsperger from Lazio on a free transfer, Grant has been keen to add more quality to a squad which only just escaped relegation last season.

Israel international Tal Ben-Haim, whom Grant also worked with at Portsmouth, is reported to be close to completing a switch to Upton Park, as the club tonight reported "further major additions are expected within the next 72 hours."

However, it has emerged the Hammers now face competition from both Liverpool and Tottenham in the chase for £12million-rated Nice striker Loic Remy.

Nevertheless, in Barrera and Piquionne, the Irons have acquired players who will certainly help inject fresh impetus into the side.

Barrera made three appearances at the World Cup, all as a substitute, as Mexico made it to the last 16.

"The fans can expect that I will give 100% to succeed for the team and to play better than I have every played before," he said.

"I am very fast and can use both feet. I like the one-on-one situations and to take on my opponent and beat my rivals. I like to excite the supporters.

"People have said that I am the sort of player that the fans want to have the ball as often as possible because I can make things happen."

Piquionne, meanwhile, has a proven track record in the English top flight, scored 11 goals in all competitions for relegated Pompey, with three of those coming in their run to the FA Cup final.

"I know Avram and I like working with him and I think he likes me," the striker said.

"I am coming to work hard for the squad and I hope we have a good season.

"Avram is a very, very good coach. Last year we had many problems at Portsmouth, but we got to the FA Cup final.

"As a player, it will be good just to concentrate on my football. When I do that, I play well and play with passion. We have the players here to have a very good season."

The West Ham squad have now headed out to Germany, where they will play Bundesliga side Borussia Monchengladbach tomorrow and then face Panathinaikos.

"I was just happy to get on and show what I can do," Edgar told www.whufc.com.

Meanwhile, Anthony Edgar is hoping his display and goal in the 2-1 win in the friendly at Peterborough will prove to be a launchpad.

"I enjoyed it in there. It is all about experience and wherever the manager puts me, I will play and try to play to my best.

"I was so pleased to get a chance to show what I can do."

Edgar maintained: "I am just going to do what I do best which is play. Hopefully I can do that and push on from there."

Even though West Ham are investing in new players this summer, owners David Gold and David Sullivan are also aware of the need to offset that against the club's crippling debt levels.

Greek club Olympiacos are said to be tracking both Alessandro Diamanti and Radoslav Kovac, while Aston Villa continue to show interest in Scott Parker, but perhaps only seriously if James Milner were to leave for Manchester City.

Those West Ham players who had some extra time off after the World Cup - including England duo Robert Green and Matthew Upson - will also join up for the Germany training camp.

On their return, the Irons head to MK Dons on July 28 and then npower Championship side Ipswich before the visit of Spanish outfit Deportivo la Coruna to Upton Park in their final pre-season fixture.