Andy Roddick began his bid for a record fifth title at Queen's Club on Tuesday by defeating 2010 semifinalist Feliciano Lopez 7-6 (2), 6-7 (5), 6-4.
The third-seeded American survived a barrage of 35 aces and claimed victory on his third match point after battling for two hours and 13 minutes.
"I love it on grass and am so happy to be back on it," said Roddick, who missed the French Open with a shoulder injury. "I feel good."
There was little to separate the two players, with Roddick holding the slightest of advantages in the opening set as he earned a break point in the sixth game and surrendered just six points on serve before dominating the tiebreaker.
Roddick then fought off two break points to hold for 4-4 in the second set, but Lopez went on to level the match by edging the tiebreaker and then broke to lead 2-1 in the final set.
But Roddick leveled at 3-3 and broke his opponent in the final game to seal the win.
Defending champion Sam Querrey also advanced into the third round with a 7-6 (6), 5-7, 6-3 win over Germany's Rainer Schuettler, although the American failed to make the most of his many break points.
"He's played a lot of grass-court matches in his career so he's a tough guy to get through and I think I did a good job," the 13th-seeded Querrey said. "I was 2 for 16 on break points, but even though my percentage was low on those I thought I did a good job of keeping my head up and staying positive."
Querrey next plays British wild card James Ward, who upset fourth-seeded Stanislas Wawrinka of Switzerland 7-6 (3), 6-3.
Juan Martin del Potro overcame an injury scare as he claimed a 6-4, 6-2 win over Uzbek Denis Istomin. The 12th-seeded Argentine struggled several times on the slippery surface, and after sliding during the fifth game of the second set, he winced in pain and called for medical attention.
But after having his left thigh strapped, he continued and closed out the match without the loss of another game.
"It was to check there was nothing dangerous," Del Potro said. "The trainer said 'you're OK, you can still play,' and he made a bandage so I could finish the match.
"I play really well. since 2009 was my last match on grass court, so it's a good first round for me."
Top-seeded Rafael Nadal will face Matthew Ebden in his opening match on Wednesday after the Australian qualifier defeated India's Somdev Devvarman 7-5, 6-3.
Second-seeded Andy Murray faces 2002 Wimbledon semifinalist Xavier Malisse, who defeated Matthias Bachinger 6-4, 6-4.