Diego Costa 's desire to win is so great that even in a simple training game the fiery striker will play on the edge , according to former team-mate Toby Alderweireld . Spain international Costa came to England with a reputation as a bullish centre forward and , as plenty of Premier League defenders will attest to , the Chelsea hitman has more than lived up to the billing . Alderweireld , on loan at Southampton , spent last season playing with the Brazil-born striker at Atletico Madrid as Diego Simeone 's side claimed a famous La Liga title . Diego Costa has been involved in numerous scuffles with defenders during the season , including a running battle with PSG defender David Luiz in Wednesday 's Champions League clash . Toby Alderweireld is likely to be tasked with stopping Diego Costa at Stamford Bridge on Sunday . Costa and Alderweireld played together at Atletico Madrid together during title winning season last year . The duo will be re-united at Stamford bridge on Sunday with Southampton still in the hunt for a top-four spot , while Chelsea will be hoping to return to winning ways after they were dumped out of the Champions League midweek by PSG . Alderweireld knows better than most what Costa is like to line up against having faced him in training and the defender is not expecting an easy ride on Sunday . 'That 's his mentality , ' the Belgium international told The Sun . 'Outside the field he 's totally different , he 's a very nice guy , good to the supporters , never in a fight , always laughing . Spain international Costa argues with PSG midfielder Thiago Motta as Thiago Silva pushes him away . Alderweireld celebrates victory against Hull with fellow teammates Jose Fonte and Morgan Schneiderlin . 'It 's strange to see him change on the field , because of his desire to win . 'Even on the training pitch , just in an easy game , four against four , he 's always on the line , and his desire is so big that sometimes he goes over it . 'It happened a lot at Atletico because the training was so crazy . '
Chelsea welcome Southampton to Stamford Bridge on Sunday . AlderweireldToby Alderweireld will be re-united with former team-mate Diego Costa . Toby Alderweireld says the striker plays with the same fiery attitude in training . Belgium international puts it down to Costa 's desire to win .