By Chris Starrs, special to EmiratesUSOpenSeries.com

ATLANTA – In posting the first upset of the BB&T Atlanta Open Monday, unseeded Jack Sock managed to maintain his intensity despite three unscheduled breaks in the action.

After besting No. 7 seed Alex Bogomolov Jr. 6-2 in the first set, Sock had to take a second-set bathroom break while trailing 3-2 (he eventually lost the set 6-4) and in the third set, a finger sliced by his racquet necessitated a medical timeout.

But the most significant – and longest – respite came during a 90-minute rain delay, when he held a 4-2 lead.

"I liked the position I was in when the rain came," said the 19-year-old Sock, who went on to defeat Bogomolov 6-4 to claim the three-set victory. "I was hoping it wouldn’t come because I was playing pretty well, but it was good to go in and cool down a little bit.

"I was hoping to come out and make a lot of first serves and have a few easy service games, but that didn’t happen. I had a long game at 4-2, and I didn’t play a very good game at 5-3, so I was happy to come back and break him at 5-4 and keep playing."

The 20-year-old Sock, a wild-card entry in the tournament, maintained his composure throughout the match, something Bogomolov – currently ranked No. 51 -- did not do, slamming his racquet and later throwing a water bottle on the court during a third-set break.

"I told myself earlier this year I wanted to maintain my professionalism and I wanted to be the most professional player on the court," said Sock. "It only makes me more motivated when I see my opponent getting angry."

Advancing to the second round, where he’ll take on former USC star and reigning NCAA champion Steve Johnson (who defeated Donald Young, 6-3, 3-6, 6-3, late Monday evening), Sock recently returned to the court after missing several months with a groin injury.

"I’ve been out for awhile and haven’t played a whole lot of matches in four months, so it was good to get a win, advance in the draw and play later in the week and hopefully keep going from there," said Sock, currently ranked No. 326.

A year removed from his high school graduation, Sock was among family members over the weekend, as he watched his brother Eric, a rising senior at Nebraska and a wild-card invitee, lose to Luca Margaroli in three sets in qualifying on Saturday.

"This was his first ATP match," Sock said of his brother. "He’s played a lot of college and junior tennis, so this was very exciting for him. He lost in three sets and played really well. Since I didn’t play until (Monday), I was able to sit and watch the whole match."