A slew of Top 10 players were in action on Day 1 of the 2022 US Open. No.7 seed Simona Halep was already upset in the opening round by Daria Snigur, and here's how the rest of Monday's Top 10 players fared:
 Maria Sakkari (GRE) def. Tatjana Maria (GER) 6-4, 3-6, 6-0
Last year's semifinalist Maria Sakkari took on a familiar Grand Slam foe in her opener. She had already played Tatjana Maria in two of the year's majors, and both previous matches promised a tight contest third time round. Sakkari had edged Maria 6-4, 7-6(2) in the first round of the Australian Open, the German's first tour-level match since returning from her second maternity leave last August. In the third round of Wimbledon, it was Maria's turn to win 6-3, 7-5 en route to a first-time Grand Slam semifinal at the age of 34.
Indeed, their New York rematch was nip-and-tuck for much of its duration. Slow to get to grips with Maria's slice, Sakkari fell behind 4-1 -- but reeled off five straight games to take the first set, impressively gritting out two multi-deuce tussles from 4-4. But a catastrophic game from the Greek featuring four double faults put her behind in the next set; stellar serving and greater aggression from Maria, who conceded only six points behind her delivery in the second set, levelled the match.
But in the decider, Sakkari got to grips with Maria's wiles by countering them with her own. She headed to net when she got the chance and came up with some magic of her own, including a backhand slice winner down the line and a forehand slice winner reflexed off a full-power return.
Next up for Sakkari will be Wang Xiyu of China, who beat France's Diane Parry 5-7, 6-3, 6-3. Wang made the semifinals in Washington earlier this month.
 Ons Jabeur (TUN) def. Madison Brengle (USA) 7-5, 6-2
Jabeur had beaten Brengle in their one previous match, in the qualifying rounds of 2020 Auckland, when both were ranked outside of the Top 80. It is safe to say much has changed for Jabeur since then, as she is now a regular in the Top 5 and reached the final of the most recent Grand Slam at Wimbledon.
Nevertheless, crafty veteran Brengle, ranked No.61, is always up for a battle, with two previous wins over Top 5 players on her resume. Indeed, the American fought back from a break down in the first set to get to 5-5. However, Jabeur converted her sixth break point of the subsequent grueling game to reclaim her break and eventually close out the set.
With the momentum firmly on her side, Jabeur drew mounting errors from Brengle as the Tunisian racked up the last five games in a row to close out her victory.
"It's nice to get the rhythm and go into the draw," Jabeur said. "I know [Brengle] was tricky. She has a lot of experience and plays different shots from other players. But I'm glad I got the win in two sets."
The win puts Jabeur one step closer to her first Round-of-16 appearance at the US Open. The Tunisian has lost in the third round in each of the last three years.
Jabeur's second-round opponent will be surging American wildcard Elizabeth Mandlik, who ousted Tamara Zidansek 5-7, 7-6(3), 6-4. Mandlik, the daughter of Grand Slam champion Hana Mandlikova, has seen her ranking rise nearly 100 spots to No.144 this month alone.
Harriet Dart (GBR) def.  Daria Kasatkina 7-6(8), 1-6, 6-3
World No.88 Dart claimed the first Top 10 win of her career on Monday, in her seventh match against Top 10 opposition. The Brit, who cracked the Top 100 for the first time in March, took two-and-a-half hours to clinch her career-best win by ranking over World No.9 Kasatkina.
After splitting the first two sets, Kasatkina, who won hardcourt titles in San Jose and Granby just this month, was twice up a break in the third set. However, Dart charged back and grabbed a key hold for 4-3, punching a volley winner into the corner to close out a tough game.
Misfires by Kasatkina gave Dart a break for 5-3, but the No.10 seed held two break points in that game to pull back on serve. Dart erased both of those chances, the second with a forehand winner smack on the sideline, and she converted her first match point with another forehand winner.
Dart will face World No.91 Dalma Galfi for a spot in the third round. Galfi of Hungary defeated Spain's Nuria Parrizas Diaz 6-4, 6-3.
 Anett Kontaveit (EST) def. Jaqueline Cristian (ROU) 6-3, 6-0
World No.2 Kontaveit claimed the last nine games of her 1-hour and 6-minute evening victory over 77th-ranked Cristian. The Estonian fired 20 winners to Cristian's 10, and Kontaveit prevailed on 85 percent of her first-service points.
Getting back on court was a victory in itself for Cristian, who was playing her first match since suffering a knee injury during her second-round match against Daria Kasatkina in Doha in February.
Kontaveit now has a marquee second-round match lined up for Wednesday: she will face 23-time Grand Slam champion Serena Williams.