Arsenal manager Arsene Wenger has signed Brazilian defender Andre Santos from Fenerbahce and expects to land Werder Bremen centre-back Per Mertesacker in the frantic final hours of the transfer window on Wednesday.
Wenger has been forced to make a series of last-ditch deals before Wednesday's 2200GMT deadline after Arsenal's miserable start to the season and Santos follows South Korea captain Park Chu-Young, who joined from Monaco on Tuesday, into the Emirates Stadium.
Santos, 28, is believed to have cost Â£6.2 million and Wenger said: "Santos is a quality player, with the ability to both defend well and get forward and help with attacks.
"He has experience in the Champions League and for Brazil and has proven he can deliver at the highest level."
Santos is likely to go straight into the team after the international break as Arsenal's only other senior left-back, Kieran Gibbs, has been struggling with injury.
"It was one of my dreams to play for a major European football club and I have accomplished this. I am very happy to be part of this team," Santos said.
Wenger also hopes to bring in Germany defender Mertesacker for around Â£8 million as he tries to shore up a leaky defence that shipped eight goals at Manchester United on Sunday.
Across north London, Tottenham finally completed the signing of England midfielder Scott Parker from West Ham in a deal believed to be worth Â£6 million.
The 30-year-old, named the English Football Writers' Association Footballer of the Year last season, was a long-term target for Harry Redknapp and the Spurs manager said: "He's a good player. I think he's what we need.
"He'll be a good addition for this team, no doubt about that."
Redknapp expected his chairman Daniel Levy to be "busy on the phone all day" as the club upped their interest in Bolton centre-back Gary Cahill.
The Spurs chief insists there is no chance of Croatia midfielder Luka Modric getting his wish to join Chelsea, but England striker Peter Crouch could leave for Sunderland, while Jermaine Jenas and Alan Hutton have been linked with Aston Villa.
After spending over Â£40 million on new signings since the end of last season, Liverpool boss Kenny Dalglish was focused on reducing the size of his squad.
England midfielder Joe Cole, who failed to shine at Anfield following his free transfer from Chelsea in 2010, joined French champions Lille in a surprise season-long loan deal.
Another Liverpool midfielder, Christian Poulsen, was also on the move to France as the Denmark international joined Evian on a one-year contract just over a season after arriving at Anfield.
Manchester City are expected to make the shock signing of the window after boss Roberto Mancini moved for Owen Hargreaves, the former England midfielder who was released by Manchester United at the end of last season after a two-year struggle with knee injuries.
Stoke are reported to have agreed a fee with Birmingham for striker Cameron Jerome, while the Championship club may also lose Scott Dann to Blackburn after the defender travelled to Ewood Park for a medical.
QPR manager Neil Warnock, bolstered by the backing of new owner Tony Fernandes, hopes to sign several more players before the window closes.
Warnock is believed to have agreed a fee with Sunderland for defender Anton Ferdinand, while Manchester City winger Shaun Wright-Phillips and his club colleague Craig Bellamy are also on QPR's wanted list.