Southampton manager Claude Puel felt Eden Hazard and Diego Costa proved the difference as Premier League leaders Chelsea ran out 4-2 winners at Stamford Bridge.

Hazard fired in his 15th league goal of the season after five minutes but ex-Chelsea midfielder Oriol Romeu levelled and Southampton were in the ascendancy before Gary Cahill headed home in first-half stoppage time.

Costa then came to the fore after the interval with a brace – his second a wonderfully worked goal featuring one-twos with Hazard and Pedro.

Ryan Bertrand nodded in a late Saints consolation and Puel was largely impressed with his players, but was left to rue two world-class talents.

"It was a better performance than against Manchester City [a 3-0 defeat in Southampton's previous match]," he told a post-match news conference.

"It's a shame in the end because we had a good game with quality, against a great, good opponent.

"But we conceded the goals in bad moments, after five minutes, just before half-time, just after half-time. It's a shame, it's a shame.

"We played against great players. Eden Hazard and Diego Costa played well and they were the difference."

Puel brought Hazard into the first-team picture as a prodigious 16-year-old at Lille and he reflected upon being on the receiving end of the mercurial Belgian's qualities.

"I'm very angry with him, of course," he joked after watching Chelsea go seven points clear of Tottenham at the top of the league.

"But he's a fantastic player. I'm happy for him. It was the same at the beginning, with the same qualities, the same ability to give assists and make penetration, with maturity and quality.

"He's having a fantastic career. Good for him."