So close! Lukaku and Werner scored...but the goals were disallowed

We are used to seeing Lukaku scoring goals every week and Werner getting his disallowed.
Both Chelsea strikers had scored in the game against Southampton, both in the first half. In the end, both their goals got disallowed
Lukaku opened the scoring, he made it 1-0 however, the flag was up as he was offside.
Later on, Werner also scored to end his drought, but the referee disallowed after a VAR review.
Werner had done everything right and scored, but at the beginning of the move, Cesar Azpilicueta committed a foul which meant the goal was chalked off.