But another error by much-maligned keeper Kepa Arrizabalaga, who was involved in a mix-up with Kurt Zouma, gifted the visitors their second goal.
"If you're going to concede those kinds of goals it doesn't matter how well you play in periods of games".
The 24-year-old, who scored against Tottenham in the League Cup in September, was a constant threat to Southampton's defence. Havertz was at fault for Southampton's first goal but recovered his composure to deliver the most promising display since his £70 million transfer from Bayer Leverkusen.
Hakim Ziyech came on for his league debut in the closing stages but Chelsea's performance levels and workrate dipped and the Saints equalised in the 92nd minute from Jannik Vestegaard's glancing header. With Senegal keeper Edouard Mendy injured, Kepa was making his first Chelsea appearance in nearly a month after being dropped following an error-strewn start to the season, but his latest blunder is likely to see him exiled again.
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Of course, that information gave a jolt to college football betting, too. Saban told players of his positive test via Zoom at 2 p.m. on Wednesday.
'Thiago Silva after his trip is not ready to play because of the travelling, ' Lampard added. Ziyech not it to start, but hopefully to get some minutes'. Ben Chilwell is fit to start at left-back. The Frenchman lines-up alongside Jorginho so Mateo Kovacic misses out.
Ralph Hasenhuttl's men capitalised on another comical Blues blunder involving Kepa in the second half to equalise with Adams eventually smashing the ball into the roof of the net.
"They were really good individual goals", Lampard said.
As for Southampton, Theo Walcott makes his first start since re-joining the club on loan from Everton.