Kicking off their trip in Littlehampton, the pair took their classic car north to an auction in Merseyside.
Mark found a rocking horse which once belonged to royalty, while Christina settled for a stilton scoop.
However, the pair clashed when it came to find out how much profit they had made in the competition.
As the disappointing action came to an end, Mark said: “I’m thinking already of round two.”
Christina then smiled: “Really? What are you going to buy next time?”
Mark then issued a chilling warning to his competitor, sternly saying: “Just watch out!”
His rival expert then put her fists up to initiate a fight, replying: “Oh really? Fighting talk. I like it. Come on. Stick ‘em up. Come on. Give me a good fight, come on!”
Defusing the situation to avoid the conflict, Mark fanned himself with a piece of paper and gasped: “I’m so hot.”
However, it was Christina’s Fry’s chocolate display cabinet then made a profit of £102 which upset Mark.
As she consoled her fellow expert, she rubbed Mark’s arm as he huffed: “Uh! Christina. I’m not a pet!”
She then asked: “Are you alright?” as Mark snapped: “I’m not speaking to you!”
Antiques Road Trip continues tomorrow on BBC One at 4.30pm.