* Southampton complete late double move
* Belgium defender, Senegal forward join south-coast club (Adds Mane signing, details quotes))
LONDON, Sept 1 (Reuters) - Premier League Southampton snapped up Belgium defender Toby Alderweireld and Senegal winger Sadio Mane to bolster their squad on transfer deadline day on Monday.
Alderweireld joined on a season-long loan deal from La Liga champions Atletico Madrid, while the 22-year-old Mane has signed a four-year contract following his transfer from Austrian champions Salzburg. No terms were disclosed.
"I am delighted we have been able to bring Toby to the club," Dutch coach Ronald Koeman told the Southampton website (www.saintsfc.co.uk).
"I know him very well because he played for some years for Ajax in Holland and he then transferred to Atletico where he hasn't been playing an awful lot."
The 25-year-old Alderweireld, who can play at centre half or right back, has won 37 caps for his country.
Mane, who was in Senegal's squad at the 2012 London Olympics, has played 15 times for his country and had been a target for several other European clubs after he scored 45 goals in 87 appearances for Salzburg, Koeman added.
"When it was clear that we would have to change a lot, Sadio was on our list of potential players," Koeman said.
"I was impressed with his qualities and with the physicality that he showed.
"He can play in different positions in the attack he can play on the left or right side and also as a number nine.
"It is incredible how many goals he has scored from his position, and I hope that he will do the same for us." (Writing by Tony Jimenez and Greg Stutchbury, editing by Pritha Sarkar)