WATCH: Mahut, Melo become stars of drama in London

After just two days, there's been plenty of drama at the ATP Finals, even in doubles. On Monday, Nicolas Mahut was taken down by an advertising block, while Marcelo Melo was felled by a Jack Sock forehand.

After running back for lob, Mahut collided with the Lacoste advertising sign (yes, he also happens to be sponsored by Lacoste).

The Frenchman hurt his shin, needing medical treatment right away and then off-court treatment as well. One of his opponents, Mate Pavic, thought there was some exaggerating going on.

"I don’t know how much of a pain he really felt or not," Pavic said. "Honestly, they played normal. By the end of the match, they broke back. He was fine. Yeah, some moments he was maybe more acting than actually he felt pain because I felt they were fine completely."

Pavic and Oliver Marach would beat Mahut and Pierre-Hugues Herbert, 6-4, 7-6 (3). Mahut called for the blocks to be made of softer material. He hopes to be ready for his next match as the ATP Finals are set up as two groups with round-robin play just like the singles draw.

In the second doubles match of the day, more drama, and alleged acting, ensued. Jack Sock, teaming up with Mike Bryan, drilled a forehand at Marcelo Melo. The Brazilian took the brunt of the impact on his right arm.

Sock and Bryan would beat Melo and Lukasz Kubot, 6-3, 7-6 (5). Judy Murray, who's son Jamie is in the draw with Bruno Soares, called the incident "MeloDrama":

In any case, a Sock forehand is not something to be taken lightly:

All eight of the doubles teams in London still have more matches left to play before the semifinalists are decided.

This Week on Tennis Channel:

ATP Finals (Sun - Sun 11.11 - 11.18) - Novak Djokovic, Roger Federer and the world's best collide in the season Finale. Live coverage begins on Tennis Channel Sunday at 7:00am EST.