U.S. Open Day 4 matches to watch: Del Potro takes on American Johnson

Five matches to watch on Day 4 on Thursday at the 2016 U.S. Open, featuring Venus Williams, Juan Martin del Potro and more.

NEW YORK – The second and final batch of second round matches will be played on Thursday at the U.S. Open. Here are the five matches you’ll want to keep an eye on, whether you're watching on TV or roaming around the grounds in Flushing Meadows.

Steve Johnson [19] vs. Juan Martin del Potro

If you’re only going to watch one match on Thursday, make it this one. Del Potro has come back this year after undergoing three left wrist surgeries to knock off Stan Wawrinka at Wimbledon, and defeat Novak Djokovic and Rafael Nadal en route to a silver medal at the Rio Games.

The 2009 U.S. Open champ, who was given a wildcard into the U.S. Open, may have a bit of a chip on his shoulder for his match again American and No. 19-seed Johnson, who beat Evgeny Donskoy in a thrilling five-setter on Tuesday. Before the tournament, Johnson said he was concerned that giving the Argentinian a wild card might take a spot away from an American, though he insisted Tuesday that his comment was taken out of context.

Either way, this one is great regardless of narrative. Both men are playing great tennis.

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Lucie Safarova vs. Simona Halep [5]

Halep has her eyes set on advancing past the semifinals at the U.S. Open for the first time in her career, but the Romanian have to get past Safarova first.

The 29-year-old will be looking to advance past the second round for the fifth time in 13 trips to Queens. Safarova has battled a bacterial infection and gastrointestinal illness this year, and while she won at the Prague Open, she was forced to retire from her first round match at the Olympics.

Halep, the favorite in the match, is 3–1 over her career against Safarova, defeating her last at the 2014 Western & Southern Open.

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Julia Goerges vs. Venus Williams [6]

Goerges and Williams are both known for powerful serves and groundstrokes which should make this one entertaining. Venus, playing in her 18th U.S. Open, will be a bit gassed after a marathon first round win over Kateryna Kozlova, which at her age could lead her into a tight match against a fresh Goerges. You’ll want to make it out to Ashe to see this.

Ivo Karlovic [21] vs. Donald Young

This one should attract a good crowd. Spectators will want to get a look at Karlovic, after the 6'10" skyscraper shattered a U.S. Open record with 61 aces in a five-set victory over Yen-Hsun Lu in the first round, and Young, a 27-year-old American, will have a large contingent behind him playing on home soil.

Both have had mixed results at this tournament, with Young going to the fourth round in Flushing twice and Karlovic advancing to the third three times, though there’s a nine-year age gap between the two so Young has time to string together more good showings.

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Jeremy Chardy vs. Grigor Dimitrov [22]

Dimitrov rolled in round one, taking his opening match over Inigo Cervantes in straight sets, but he should have a tougher time with his second-round matchup. Frenchman and World No. 55 Jeremy Chardy hasn’t had the greatest year, but he did reach the third round at the French Open. Plus, the two played a five-setter at the Australian Open back in 2012.

Dimitrov entered this tournament with a head of steam, and should win this match, but it should be competitive.